392 research outputs found
TDZ AND 4-CPPU in Gamborg B5 salts with MS vitamins doubles embryogenic 191 response from male flowers of EA-AAA banana.
Conventionally, auxins have been used in MS medium in combination or without purine-based cytokinins for induction of embryogenesis in EA-AAA banana (Musa spp.). Besides, low embryogenic response, it has been rare for more than two cultivars to respond similarly to a single treatment. This study investigated the efficacy of urea-type cytokinins, N-phenyl-N’-1,2,3-thidiazol-5-ylurea (TDZ) and N-(2-chloro-4-pyridyl)-N'-phenylurea (4-CPPU); and salt formulations, Chu (N6), Eriksson, Gamborg B5, MS, Nitsch, NLN, SH and White for embryogenic callus induction in different EA-AAA banana cultivars. Immature male flowers of cultivars Mpologoma, Mbwazirume, Nakabululu, Nakinyika and Nfuuka were cultured on callus induction medium, supplemented with different TDZ and 4-CPPU combinations. Most of the cultivars had embryogenic response to the medium with 10μM TDZ+10μM CPPU. Cultivar Nakabululu recorded 22.2% embryogenic response, followed by Mwazirume (5.7%), Nakinyika (5.3%) and Mpologoma (4.6%). Cultivar Nfuuka had 9.1% embryogenic response on 15μM TDZ+15μM CPPU. When cultivars Mpologoma and Nakinyika were cultured on the same medium containing 10μM TDZ+10μM CPPU, but the MS salts substituted with the other salt formulations, their cultures recorded 11.4 and 8.3% embryogenic response, respectively to Gamborg B5 salts; which was almost twice their response to MS medium. The results suggested that TDZ and 4-CPPU, particularly in Gamborg B5 salt formulation, could increase percentage of embryogenic callus induced from male flowers of EA-AAA banana cultivars, and would improve plant regeneration and consequently help in the process of genetic improvement of EA-AAA banana.Key Words: Cytokinins, embryogenic response, Musa spp., Thidiazuro
BANANA JUICE AS AN ALTERNATIVE ENERGY SOURCE FOR BANANA IN VITRO GROWTH MEDIUM
Energy sources in tissue culture media are important for plants whose
photosynthetic efficiency is insufficient under in vitro conditions.
However, the cost of tissue culture grade energy sources is high, thus
making tissue culture derived plantlets expensive. The cost of table
sugar commonly used in commercial tissue culture laboratories and a
substitute for tissue culture grade sucrose in Uganda, is also
relatively high given the volumes used. The aim of this study was to
evaluate the possibility of exploiting banana ( Musa spp.) juice, as
an energy source in place of table sugar or tissue culture grade
sucrose. Banana juice was extracted from the locally available East
African Highland Banana (EAHB) beer cultivars, Mbidde-Kabula, Pisang
awak (Kayinja) and Km 5, and used at levels of 20, 30, 40 and 50 ml
l-1. The quality and amount of juice necessary to support in vitro
growth of cooking EAHB cultivars Nakabululu, Nakitembe and Nakinyika
was evaluated. The juice had varied composition of salts, sugars and
organic acids; but with pH compared with table sugar solution. The
highest number of shoots and shoot height was observed when bananas
were cultured on media supplemented with 50 ml l-1 Kayinja juice. This
response was greater than that observed with culture media supplemented
with the control energy source of 30 g l-1 of table sugar. Results also
showed that banana juice not only enhanced micropropagation but also
improved in vitro plantlet vigour and reduced the cost of energy
sources by 30%.Les sources d\u2019\ue9nergies sont importantes dans les milieux de
culture in-vitro des plantes dont l\u2019efficacit\ue9
photosynth\ue9tique est insuffisante dans les conditions de culture
in-vitro . Cependant, le co\ufbt des sources d\u2019\ue9nergies
utilis\ue9es en culture in-vitro de tissus est \ue9lev\ue9, ceci
rend couteux les plantules produites par culture in-vitro. Le co\ufbt
du sucre de table habituellement utilis\ue9 dans les laboratoires
commerciaux de culture de tissus in-vitro ainsi que celui du substitut
de sucrose utilis\ue9 en Ouganda reste relativement \ue9lev\ue9,
\ue9tant donn\ue9 les volumes utilis\ue9s. L\u2019objectif de
cette \ue9tude \ue9tait d\u2019\ue9valuer la possibilit\ue9
d\u2019exploiter le suc de bananier ( Musa spp.), comme une source
d\u2019\ue9nergie en lieu et place du sucre de table ou du sucrose.
Le suc de bananier a \ue9t\ue9 extrait des vari\ue9t\ue9s de
bananier localement disponible\ua0; bananier de terre ferme de
l\u2019Afrique de l\u2019Est (EAHB), Mbidde-Kabula, Pisang awak
(Kayinja) and Km 5, et utilis\ue9 \ue0 diff\ue9rentes
concentrations telles que 20, 30, 40 and 50 ml l-1. La qualit\ue9 et
la quantit\ue9 de suc n\ue9cessaire pour assurer la croissance
in-vitro des vari\ue9t\ue9s EAHB, Nakabululu, Nakitembe and
Nakinyika a \ue9t\ue9 \ue9valu\ue9. Le suc avait des
concentrations vari\ue9es en sels, sucres et acides organiques; mais
avec un pH comparable \ue0 celui du sucre de table en solution. Le
plus grand nombre de rejetons et les pousses les plus hautes ont
\ue9t\ue9 obtenues lorsque les tissus du bananier sont
cultiv\ue9s dans un milieu contenant 50 ml l-1 de suc de Kayinja.
Cette r\ue9ponse \ue9tait plus \ue9lev\ue9e que celle obtenue
avec culture sur un milieu t\ue9moin (30 g l-1 de sucre de table).
Les r\ue9sultats indiquent que le suc de bananier au-del\ue0 de
renforcer la micro propagation, am\ue9liore aussi la vigueur des
plantules en verre et r\ue9duit de 30% le co\ufbt des sources
d\u2019\ue9nergies utilis\ue9es en culture de tissus in-vitro
Prevalence of viruses infecting cowpea in Uganda and their molecular detection
The main areas for cowpea cultivation in Uganda were surveyed in June and October 2006 for viruses affecting the crop. Seed and leaf samples from symptomatic and asymptomatic plants were collected from farmers’ fields and analysed for infecting viruses using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). The viruses detected in the leaf and seed samples were: cucumber mosaic cucumovirus (CMV), cowpea mild mottle calarvirus (CPMMV), cowpea mottle carmovirus (CPMoV), Cowpea chlorotic mottle bromovirus (CCMV), Cowpea yellow mosaic comovirus (CYMV), cowpea severe mosaic comovirus (CPSMV), cowpea aphid-borne mosaic potyvirus (CABMV) and Southern bean mosaic sobemovirus (SBMV). CPMV was detected only in leaf samples. CMV and CABMV were later confirmed using reverse transcription polymerase chain reaction (RT-PCR). Of the viruses detected in leaf samples, 53.26% occurred as single infections, 24.46% dual and 22.28% multiple infections. Similarly, analysis of seed samples revealed infection of 40.6, 34.6 and 24.8% for single, dual and multiple infections, respectively. Multiple virus infections were associated with more disease severity and higher yield losses. The seed transmission levels of 23.0, 20.3 and 16.4% were recorded for CMV, CPMMV and CABMV, respectively. This study identified six more viruses in addition to what was previously reported in the country, of which eight were seed-borne. This necessitates the need for the production and use of virus-free seeds, development of virus resistant genotypes and adoption of efficient seed certification systems.Keywords: Vigna unguiculata, disease incidence, seed-borne viruses, ELISA, (RT-PCR
Induction of somatic embryogenesis in recalcitrant sweetpotato (Ipomoea batatas L.) cultivars
Genetic transformation is considered as one of the most promising options for improvement of crop traits. Current transformation methods for sweetpotato depend on plant regeneration through organogenesis or somatic embryogenesis. Somatic embryogenesis and plant regeneration at a high frequency has been restricted to a few sweetpotato varieties. Three auxins namely: 2,4-dichlorophenoxyacetic acid (2,4-D), 4-fluoroamphetamine (4-FA) and 4,5-trichlorophenoxyacetic acid (2,4,5-T) were investigated in this study for enhancing somatic embryogenesis from various plant organs of recalcitrant African sweetpotato cultivars. 2,4-D was found to be the best (p . 0.05) for induction of embryogenic callus. Cultivar Bwanjule had the highest (20.2%) embryogenic callus frequency among the five African cultivars tested. The highest number of plants in this study was regenerated from the non-African cultivar variety Jonathan on media supplemented with 0.2 mg Zeatin. The emergence of roots from callus of recalcitrant Ugandan cultivars and the comparable high embryogenic responses in this work demonstrate the potential for regenerating plants from African cultivars that have not been regenerated before. The regeneration of roots in this work could be useful for the initiation of root cultures. The most important application of this work is in genetic transformation of sweet potato, particularly for improvement of resistance to weevils.Key words: Embryogenesis, plant growth regulators, plant regeneration, Ipomoea batatas
A Systematic Review and Meta-Analysis of Self-Guided Online Acceptance and Commitment Therapy as a Transdiagnostic Self-Help Intervention
Online Acceptance and Commitment Therapy (ACT) interventions use websites and smartphone apps to deliver ACT exercises and skills. The present meta-analysis provides a comprehensive review of online ACT self-help interventions, characterizing the programs that have been studied (e.g. platform, length, content) and analyzing their efficacy. A transdiagnostic approach was taken, including studies that addressed a range of targeted problems and populations. Multi-level meta-analyses were used to nest multiple measures of a single construct within their respective studies. A total of 53 randomized controlled trials were included (n = 10,730). Online ACT produced significantly greater outcomes than waitlist controls at post-treatment for anxiety, depression, quality of life, psychological flexibility, and all assessed outcomes (i.e. omnibus effect), which were generally maintained at follow-up. However, only psychological flexibility and all assessed outcomes at post-treatment were found to be significantly greater for online ACT when compared to active controls, with no significant follow-up effects. Overall, these results further clarify that ACT can be effectively delivered in an online format to target a wide range of mental health concerns, although it is less clear if and when online ACT is more efficacious than other online interventions
TDZ AND 4-CPPU IN GAMBORG B5 SALTS WITH MS VITAMINS DOUBLES EMBRYOGENIC RESPONSE FROM MALE FLOWERS OF EA-AAA BANANA
Conventionally, auxins have been used in MS medium in combination or
without purine-based cytokinins for induction of embryogenesis in
EA-AAA banana ( Musa spp.). Besides, low embryogenic response, it has
been rare for more than two cultivars to respond similarly to a single
treatment. This study investigated the efficacy of urea-type
cytokinins, N-phenyl-N\u2019-1,2,3-thidiazol-5-ylurea (TDZ) and
N-(2-chloro-4-pyridyl)-N\u2019-phenylurea (4-CPPU); and salt
formulations, Chu (N6), Eriksson, Gamborg B5, MS, Nitsch, NLN, SH and
White for embryogenic callus induction in different EA-AAA banana
cultivars. Immature male flowers of cultivars Mpologoma, Mbwazirume,
Nakabululu, Nakinyika and Nfuuka were cultured on callus induction
medium, supplemented with different TDZ and 4-CPPU combinations. Most
of the cultivars had embryogenic response to the medium with 10\ub5M
TDZ+10\ub5M CPPU. Cultivar Nakabululu recorded 22.2% embryogenic
response, followed by Mwazirume (5.7%), Nakinyika (5.3%) and Mpologoma
(4.6%). Cultivar Nfuuka had 9.1% embryogenic response on 15\ub5M
TDZ+15\ub5M CPPU. When cultivars Mpologoma and Nakinyika were
cultured on the same medium containing 10\ub5M TDZ+10\ub5M CPPU,
but the MS salts substituted with the other salt formulations, their
cultures recorded 11.4 and 8.3% embryogenic response, respectively to
Gamborg B5 salts; which was almost twice their response to MS medium.
The results suggested that TDZ and 4-CPPU, particularly in Gamborg B5
salt formulation, could increase percentage of embryogenic callus
induced from male flowers of EA-AAA banana cultivars, and would improve
plant regeneration and consequently help in the process of genetic
improvement of EA-AAA banana.Conventionnellement, les auxines ont \ue9t\ue9 utilisees dans le
medium MS en combinaison avec ou sans cytokinines \ue0 base de purine
pour induction de l\u2019embryogen\ue8se dans la banane EA-AAA (
Musa spp.). En plus d\u2019une faible r\ue9ponse
embryog\ue9nique, il a \ue9t\ue9 rare pour plus de deux cultivars
de r\ue9pondre de fa\ue7on similaire \ue0 un seul traitement.
Cette \ue9tude a \ue9t\ue9 conduite pour \ue9valuer
l\u2019efficacit\ue9 des cytokinines de type urea,
N-phenyl-N\u2019-1,2,3-thidiazol-5-ylurea (TDZ) et
N-(2-chloro-4-pyridyl)-N\u2019-phenylurea (4-CPPU)\ua0; et les
formulations du sel, Chu (N6), Eriksson, Gamborg B5, MS, Nitsch, NLN,
SH et blanc pour l\u2019 induction du callus embryog\ue9nique dans
diff\ue9rents cultivars de banane EA-AAA. Des cultivars Mpologoma des
fleurs males immatures Mbwazirume, Nakabululu, Nakinyika et Nfuuka
\ue9taient cultiv\ue9s sur le medium d\u2019induction du callus,
suppl\ue9ment\ue9e avec diff\ue9rentes combinaisons de TDZ et
4-CPPU. La plupart des cultivars avaient une r\ue9ponse
embryog\ue9nique au medium avec 10\ub5M TDZ+10\ub5M CPPU. Le
cultivar Nakabululu a r\ue9alis\ue9 22.2% de r\ue9ponse
embryog\ue9nique, suivi de Mbwazirume (5.7%), Nakinyika (5.3%) et
Mpologoma (4.6%). Le cultivar Nfuuka avait 9.1% de r\ue9ponse
embryog\ue9nique sur 15\ub5M TDZ+15\ub5M CPPU. Lorsque les
cultivars Mpologoma et Nakinyika \ue9taient cultiv\ue9s sur le
m\ueame medium contenant 10\ub5M TDZ+10\ub5M CPPU, mais les sels
MS substitu\ue9s par d\u2019autres formulations de sels, leurs
cultures ont enregistr\ue9 11.4 et 8.3% de r\ue9ponses
embryog\ue9niques, respectivement, aux sels Gamborg B5; qui faisait
presque le double de leur r\ue9ponse au medium MS. Les r\ue9sultats
ont sugg\ue8rent que TDZ et 4-CPPU, particuli\ue8rement dans la
formulation du sel Gamborg B5, pourrait augmenter le pourcentage induit
du callus embryog\ue9nique des fleurs males des cultivars de banane
EA-AAA et pourrait am\ue9liorer la r\ue9g\ue9n\ue9ration des
plants et en cons\ue9quence aider dans le processus de
l\u2019am\ue9lioration g\ue9n\ue9tique de la banane EA-AAA
The study of fisheries contribution to the people's diet
Uganda comprises of about 241,000 km2 or 18% is water (Lakes and Rivers, swamps, dams, valley tanks and fish ponds) (MPED 1991a). It is estimated that these waters produce 219,.000 tonnes 'of fish (UFD 1991) major contributors being Lake Victoria followed by Kyoga. Other important producers include Lakes Albert, Edward and George and Albert "Nile. In terms of species composition, Nile perch and Tilapine species represent by far the most significant proportions of the catch accounting for 51% to 39% respectively (UFD 1989). Uganda has a population of 16.6 million people (1991 census) of whom 90% live in rural areas with major occupation being peasant agriculture. This
population is made up of more than 52 ethnic groupings whose., diet is varied depending on cultural influences, geographical location and climate. Per capita fish consumption is estimated ,at 12 kg per annum (UFD 1990).
The average diet in Uganda particularly among the poor majority of population is unbalanced, mainly based on starchy food crops as roots and . tubers, cereals and banana. There are indicators of high prevalence of 'chronic malnutrition of children of 12 -56 months (SSALI and SEWANKAMBO 1991). There are also diseases like Goitre, Rickets and Blindness in the adult population caused by nutritional defficiencies. The production and consumption of protein food is still under-developed, presenting a potential to be exploited
Proliferation and shoot recovery among the East African highland banana
Production of East African highland banana (EA-AAA banana) ( Musa
spp.) is limited by scarcity of planting materials, attributable to
their low natural proliferation ability. Under natural field
conditions, the EA-AAA bananas greatly differ in suckering ability. In
vitro micropropagation has been adopted as an alternative means for
production of banana planting materials. In this study, the in vitro
proliferation potential of seven EA-AAA banana cultivars, with
different suckering ability was determined on Murashige and Skoog (MS)
medium, to enhance development of micropropagation protocols for their
multiplication. Commonly cultivated non EA-AAA banana cultivars were
used to compare proliferation of the seven EA-AAA cultivars. There was
a wide variation in the number and morphology of shoots and buds
produced by the different cultivars. The EA-AAA banana cultivars
produced 3-4 new shoots in each subculture cycle, and 57-169
recoverable shoots from one starting shoot-tip explant in 18 weeks.
Non-EA-AAA banana cultivars, namely Sukali Ndizi (AAB) and Yangambi Km5
(AAA), showed higher proliferation levels, 5 and 9 shoots, from each
subculture cycle and 322 and 352 recoverable shoots, respectively. The
EA-AAA banana cultivars showed higher efficiency to produce recoverable
shoots from shoot buds (53 - 66% except for cv. Kabula at 36%) compared
to Sukali Ndizi (52%) and Yangambi Km5 (32%). The study demonstrates
the potential of in vitro approach for production of banana planting
materials. In vitro proliferation ability and in particualr efficiency
to produce recoverable shoots of the different EA-AAA banana cultivars
could be improved by varying the culture conditions during the
subsequent subculture cycles.La production de la banane (EA-AAA banana) ( Musa spp.) dans les
montagnes de l\u2019Afrique de l\u2019Est est limit\ue9e par le
manque du mat\ue9riel de plantation suite \ue0 leur base
capacit\ue9 de prolif\ue9ration. En conditions naturelles au
champs, les bananes EA-AAA different consid\ue9rablement en leur
capacit\ue9 de succion. La propagation in vitro a \ue9t\ue9
adopt\ue9e comme moyen alt\ue9rnatif pour la production du
mat\ue9riel de plantation de la banana. Dans cette \ue9tude, le
potentiel de prolif\ue9ration in vitro de sept cultivars de banana
EA-AAA de capacit\ue9 de succion diff\ue9rente, \ue9tait
d\ue9termin\ue9 sur les media de Murashige et Skoog (MS), afin
d\u2019am\ue9liorer le d\ue9veloppement de protocoles de
micropropagation pour leur multiplication. Des cultivars
commun\ue9ment cultiv\ue9s autre que la banana EA-AAA \ue9taient
utilis\ue9s pour faire la comparaison avec la proliferation des sept
cultivars EA-AAA. Il y\u2019avait eu une large variation dans le
nombre et la morphologie des pousses et bourgeons de diff\ue9rents
cultivars. Les cultivars de bananes EA-AAA ont produit 3-4 nouvelles
pousses dans chaque cycle de sous culture et 57-169 pousses
recouvrables d\u2019un explant de pousse dans 18 semaines. Les
cultivars de bananes non-EA-AAA nom\ue9ment Sukali Ndizi (AAB) and
Yangambi Km5 (AAA), ont montr\ue9 de niveaux \ue9lev\ue9s de
proliferation, 5 et 9 pousses de chaque cycle de sous culture et 322 et
352 pousses recouvrables, respectivement. Les cultivars de bananes
EA-AAA ont montr\ue9 un niveau d\u2019efficacit\ue9
\ue9lev\ue9 quant \ue0 la production de de pousses recouvrables
\ue0 partir de bourgeons (3566% except\ue9 pour cv. Kabula \ue0
36%) en comparaison avec Sukali Ndizi (52% et Yangambi km5 (32%). Cette
\ue9tude d\ue9montre le potentiel de production du mat\ue9riel de
plantation de la banana par l\u2019approche in vitro. La capacit\ue9
de proliferation in vitro et en particulier l\u2019efficacit\ue9 de
produire de pousses recouvrables de diff\ue9rents cultivars pourrait
\ueatre am\ue9lior\ue9 en variant les conditions de cultrure
Durant les cycles sous culturales
THIDIAZURON IMPROVES ADVENTITIOUS BUD AND SHOOT REGENERATION IN RECALCITRANT SWEETPOTATO
Induction of adventitious buds and shoots from intact leaves and stem
internode segments of two recalcitrant Ugandan sweetpotato ( Ipomoea
batatas L.) cultivars was investigated in vitro on Murashige and
Skoog (MS) medium, supplemented with 3 different levels (0.5, 2.0 and
4.0 \u3bcM) of Thidiazuron (TDZ). Shoots were regenerated in all TDZ
concentrations in cvs. Kyebandula and Bwanjule. The inclusion of 0.25
\u3bcM \u3b1-Naphthalene acetic acid (NAA) in MS medium, containing
TDZ (0.5 \u3bcM), improved shoot regeneration frequency from 12.1 to
22.6% for cv. Kyebandula stems and from 21.61 to 42.9% for cv. Bwanjule
stems. However, there was about 10% reduction in adventitious bud
induction frequency for both cultivars, when NAA was included in the
medium. The highest frequency (66.7%) of adventitious bud induction was
achieved from stem explants of cv. Kyebandula. The conversion of
adventitious buds into shoots was improved when TDZ was reduced or
completely removed in subsequent stages of culture. The number of
explants forming shoots was significantly (P<0.001) higher when stem
explants were cultured for 7 days on TDZ-supplemented MS medium before
transfer to TDZfree MS medium supplemented with NAA. Stem internode
pieces from position 3 were the best (70.0%) in adventitious bud
formation. However, most buds (76.2%) were not converted to shoots. The
most important application of the de novo regeneration protocol
developed in this study is in genetic transformation for improvement of
sweetpotato productivity.L\u2019 induction des bourgeons adventices et des pousses \ue0
partir des feuilles intacts et des tiges des segments internodes de
deux patates douces ( Ipomoea batatas L.) Ugandaises recalcitrantes
\ue9tait \ue9tudi\ue9e en milieu in vitro sur le m\ue9dia
Murashige et Skoog (MS) suppl\ue9ment\ue9 avec 3 niveaux
diff\ue9rents (0.5, 2.0 et 4.0 \u3bcM) de Thidiazuron (TDZ). Les
pousses \ue9taient r\ue9g\ue9n\ue9r\ue9es dans toutes les
concentrations TDZ dans les cvs. Kyebandula et Bwanjule.
L\u2019inclusion de 0.25 \u3bcM \u3b1-Naphthal\ue8ne d\u2019
acide ac\ue9tique (NAA) dans le m\ue9dia MS contenant le TDZ (0.5
\u3bcM) a am\ue9lior\ue9 la fr\ue9quence de la
r\ue9n\ue9g\ue9n\ue9ration des pousses de 12.1 \ue0 22.6%
pour les pousses cv. Kyebandula et de 21.61 \ue0 42.9% pur les
pousses cv. Bwanjule. Cependant, il y a eu environ 10% de
r\ue9duction en termes de la fr\ue9quence d\u2019induction des
bourgeons adventices pour les deux cultivars lorsque NAA \ue9tait
inclu dans le m\ue9dia. La fr\ue9quence la plus \ue9lev\ue9e
(66.7%) d\u2019induction des bourgeons adventices \ue9tait
r\ue9alis\ue9e des explants des tiges de cv. Kyebandula. La
conversion des bourgeons adventices en pousses \ue9tait
am\ue9lior\ue9e lorsque TDZ \ue9tait r\ue9duit ou
compl\ue8tement enlev\ue9 des \ue9tapes de cultures
subs\ue9quentes. Le nombre d\u2019explants formant les pousses
\ue9tait significativement (P<0.001) sup\ue9rieur lorsque les
explants des tiges \ue9taient cultiv\ue9s pendant 7 jours sur le
m\ue9dia MS suppl\ue9ment\ue9 par TDZ avant le transfert dans le
m\ue9dia MS sans TDZ avec pour suppl\ue9ment NAA. Les morceaux de
tiges internodes de la position 3 \ue9taient le meilleur (70.0%) en
formation de bourgeons adventices. Cependant, plus de bourgeons (76.2%)
n\u2019\ue9taient pas converties en pousses. L\u2019application la
plus importante du protocol de la r\ue9g\ue9n\ue9ration de novo
d\ue9v\ue9lopp\ue9e dans cette \ue9tude reside dans la
transformation g\ue9n\ue9tique pour l\u2019am\ue9lioration de la
productivit\ue9 de la patate douce
TRANSIENT EXPRESSION OF \u3b2-GLUCURONIDASE IN RECALCITRANT UGANDAN SWEETPOTATO AND PUTATIVE TRANSFORMATION WITH TWO CRY GENES
Sweetpotato ( Ipomoea batatas Lam.) has high potential to contain
hunger, malnutrition and poverty in sub-Saharan Africa (SSA), since it
gives early yield with few inputs. However, productivity of the crop in
Africa is very low due to various challenges, such as severe viral
diseases and increasing attacks by sweetpotato weevils, Cylas
puncticollis and C. brunneus . Effective resistance to weevils has
not been identified in the sweetpotato gene pool. On the other hand,
the weevil-resistance genes, cry7Aa1 and cry3Ca1 were assembled into a
plasmid vector for use in genetic transformation of African sweetpotato
cultivars. The parameters for efficient transfer of these genes and the
conditions for de novo regeneration optimised in preliminary studies
were used in the genetic transformation of Ugandan landrace
\u2018Kyebandula\u2019 with Agrobacterium tumefaciens EHA 105
harbouring the plasmid pCIP84, which contains cry7Aa1, cry3Ca1 and
nptII in its T-DNA. Fifty-four percent of the explants formed
adventitious buds. With a mean of 7 buds formed per explant, 6.0%
explants formed shoots with a mean of one shoot per explant for those
explants that formed shoots on medium containing 50 mg L-1 kanamycin as
a selection agent. PCR analysis using primers for cry7Aa1 showed that
the transformation efficiency could be as high as 2%. These data
highlight the potential of genetic transformation in transferring
resistance genes and pave way for enhancement of food security through
production of adapted sweetpotato weevil resistant cultivars.La patate douce ( Ipomoea batatas Lam.) a un potentiel de contenir la
faim, la malnutrition et la pauvret\ue9 en Afrique Sub Saharienne
\ue9tant donn\ue9 sa pr\ue9cocit\ue9 et son grand rendement
avec peu d\u2019intrants. Par ailleurs, sa productivit\ue9 est trop
basse due aux diverses contraintes li\ue9es aux maladies virales et
attaques sans cesse croissante des charan\ue7ons Cylas puncticollis
and C. brunneus . Une r\ue9sistance efficace au charan\ue7on
n\u2019a pas encore \ue9t\ue9 identifi\ue9e dans la collection
des g\ue8nes de la patate douce. D\u2019autre part, les g\ue8nes
de r\ue9sistance aux charan\ue7ons, cry7Aa1 et cry3Ca1 \ue9taient
assembl\ue9es un vecteur de plasmide pour utilisation dans la
transformation g\ue9n\ue9tique des cultivars de patate douces
africaines. Les param\ue8tres pour transfert d\u2019efficacit\ue9
de ces g\ue8nes et les conditions de r\ue9g\ue9n\ue9ration de
novo optimis\ue9es dans des \ue9tudes pr\ue9liminaires
\ue9taient utilis\ue9es dans la transformation g\ue9n\ue9tique
du landrace ougandais \u2018Kyebandula\u2019avec l\u2019
Agrobacterium tumefaciens EHA 105 portant le plasmide pCIP84,
contenant les cry7Aa1, cry3Ca1 et nptII dans son T-ADN. Cinquante
quatre pourcent des explants ont form\ue9 des bourgeons adventices.
Avec une moyenne de 7 bourgeons par explant, 6.0% d\u2019explants ont
form\ue9 des tiges avec une moyenne d\u2019une tige par explant pour
ces explants qui ont form\ue9 des tiges sur le media contenant 50 mg
L-1 de kanamycine comme agent de s\ue9lection. L\u2019analyse par
PCR utilisant des primers pour cry7Aa1 a montr\ue9 que la
transformation efficace pourrait \ueatre aussi \ue9lev\ue9e que
2%. Ces donn\ue9es soulignent le potentiel de transformation
g\ue9n\ue9tique dans le transfert des g\ue8nes de r\ue9sistance
et un moyen d\u2019am\ue9liorer la s\ue9curit\ue9 alimentaire
\ue0 travers la production des cultivars de r\ue9sistance
adapt\ue9e aux charan\ue7ons de la patate douce
- …