Heritable Effect of Plant Water Availability Conditions on Restoration of Male Fertility in the “9E” CMS-Inducing Cytoplasm of Sorghum

Heritable changes of phenotype arising in plant ontogenesis by the influence of environmental factors belong to the most intriguing genetic phenomena. An unusual inheritance pattern was detected during examination of male fertility restoration in the CMS-inducing “9E” type cytoplasm of sorghum: Rf-genes were functional in self-pollinated progeny of F1 hybrids yet were either not expressed or poorly expressed in backcrosses of these hybrids to CMS-lines with the same cytoplasm type. In experiments on parallel growing of the same F1 hybrid combinations in the “dry plot” and in the “irrigated plot,” it was found that high level of plant water availability during panicle and pollen developmental stages significantly increased male fertility of F1 and test-cross hybrid populations, in which fertility-restoring genes were in heterozygote state, whereas in F2 populations the influences of water availability conditions cause less pronounce effects. Similarly, male-sterile F1 plants, being transferred from the “dry plot” to greenhouse, produced male-fertile panicles. In addition, male-sterile plants from F2 families, which segregated-out as recessives, being transferred to greenhouse also produced male-fertile panicles. In the progenies of these revertants that were grown in field conditions and in the “dry plot,” stable inheritance of male fertility for three cycles of self-pollination was observed, and a number of stable fertile lines in the “9E” cytoplasm were obtained. However, in test-crosses of these fertile lines to CMS-lines with the “9E” cytoplasm restoration of male fertility was not observed, except the progeny of one revertant that behaved as fertility-restorer line. These data suggest that the functional state of fertility-restoring genes for the “9E” sorghum cytoplasm is epigenetically regulated trait established by the influence of environmental factors and is transmitted to sexual generations

Effect of cytoplasmic male sterility type on chlorophyll content in leaves of grain sorghum hybrids

New types of CMS-inducing cytoplasms cannot be applied to hybrid sorghum breeding without knowledge of their effects on major biological and commercial plant traits. In our studies of F1 hybrids obtained by crossing of two sets of isonuclear CMS lines (with nuclear genomes of cv. Pishchevoye 614 (P614) and Zhelyozyornoye 10 (Zh10)) to two pollen parents (cv. Pishchevoye 35 (P35) and Mercury), we focused our attention on the effects of A3, A4, 9E, and M35-1A cytoplasms on chlorophyll content at different developmental stages of sorghum plants. It was found that hybrids with different types of male-sterile cytoplasm differed in chlorophyll content, and the genotypes of the CMS line and the pollen parent influenced the manifestation of cytoplasmic differences. In the F1 hybrids obtained with CMS lines possessing the P614 genome, sterile M35-1A cytoplasm increased chlorophyll a content, in comparison to 9E cytoplasm. In the F1 hybrids obtained with CMS lines with the Zh10 genome and the P35 pollen parent, sterile A4 cytoplasm increased the sum of chlorophyll a and b, in comparison to A3 and 9E cytoplasms, whereas no differences were recorded in the F1 hybrids obtained with Mercury. The F1 hybrids obtained with CMS lines with the P614 genome showed heterosis for total chlorophyll content at the tillering stage. Overdominance of this trait was observed in hybrids with M35-1A cytoplasm; true heterosis exceeded analogous indices in 9E cytoplasm by 19.0 %, and the hypothetical heterosis, by 20.6 %. These data demonstrate that the application of new types of CMS-inducing cytoplasms allows raise of F1 hybrids with heterosis for chlorophyll content. Thus, such types can be used to increase hybrid productivity

Influence of different types of sterile cytoplasms (A3, A4, 9E) on the combining ability of CMS lines of sorghum

Investigation of the effect of the cytoplasm on the combining ability (CA) of lines with cytoplasmic male sterility (CMS) is of considerable interest in terms of understanding the genetic functions of the cytoplasm and for practical purposes to create hybrids with improved economically valuable traits. In order to investigate the effect of different types of sterile cytoplasm (A3, A4, 9E) on CA in sorghum, we studied the manifestation of a number of biological and agronomic traits in 54 F1 hybrid combinations obtained using iso-nuclear CMS lines with the nuclear genome of the line Zheltozernoye 10, differing only in the types of sterile cytoplasm (A3, A4 and 9E). Eighteen varieties and lines of grain sorghum developed at the Russian Research and Project-technological Institute of Sorghum and Maize were used as paternal parents. The CA was determined by the topcross method. F1 hybrids and their parents were grown in 2015–2017 in conditions of insufficient (2015–2016: HTC (hydro-thermal coefficient) = 0.32–0.66), or good water availability conditions (2017: HTC = 1.00). On average, for three years of testing, a positive effect of the 9E cytoplasm on the general combining ability (GCA) (0.63) and negative effects of the A3 and A4 cytoplasms (–0.32 and –0.31) for the inflorescence length were noted. In dry seasons, significant positive effects of the 9E cytoplasm on GCA for the length of the largest leaf, and positive effects of the A3 cytoplasm on GCA for the plant height, and negative effects of the A4 cytoplasm on GCA for these traits were observed. No differences were observed during the wet season. The type of CMS did not affect the GCA for the width of the largest leaf and grain yield. The dispersion of specific combining ability (SCA) in the dry seasons was significant for the following traits: leaf length, plant height, panicle length and width, and grain yield, the 9E cytoplasm had the highest SCA dispersion, whereas the A4 cytoplasm had the smallest one. The data obtained indicate that different types of sterile cytoplasm of sorghum make a different contribution to CA under conditions of drought stress

Improvement of grain sorghum nutritive properties using modern genetic and biotechnological methods

The paper presents a review of the studies on the use of genetic engineering and genome editing tools for improving nutritional properties of sorghum grain. As a result of experiments performed over the past 5-7 years by several research groups, the created transgenic lines carry genetic constructs for RNA silencing of different kafirin sub-classes (prolamins of sorghum grain). The CRISPR/Cas9 genome editing experiments have yielded mutants with deletions and insertions in the signal sequence of the gene encoding the 22 kDa α-kafirin in sorghum. These lines and mutants were characterized by improved in vitro digestibility of grain proteins, altered ultrastructure of protein bodies and an increased content of lysine. RNA silencing of α-kafirin increased the digestibility of proteins of both raw and cooked flour, while silencing of γ-kafirin led to improved digestibility of proteins of only raw flour. The lines with α-kafirin silencing have kernels with the floury endosperm type that discourages their direct commercial use because of fragility and reduced tolerance to fungal contamination; however, these lines can be used as donors of high digestibility trait when crossed with sorghum lines adapted to local conditions to improve their nutritional value. Kernels of the lines with γ-kafirin silencing may have different endosperm types: floury, vitreous, or a modified type with vitreous endosperm interspersed in the floury endosperm. This fact indicates the possibility of producing agronomically important sorghum lines with high kafirin digestibility and hard endosperm. The increased lysine level in kernels of sorghum lines with the suppressed synthesis of kafirins may be caused by rebalancing of protein synthesis in endosperm of developing kernels due to the synthesis of other proteins, including those with a higher content of essential amino acids. Alongside with improving the digestibility of kafirins, the genetic engineering approach allowed the creation of sorghum lines with a high content of provitamin A in grain and its increased stability during long-term storage. The results of these works show that it is promising to use RNA-interference and genome editing for creating sorghum lines with improved nutritional value of grain

Grain and seed protein functionality

Editado por Jiménez-López, José Carlos (CSIC

Spelling improvement through letter-sound and whole-word training in two multilingual Greek- and English- speaking children

Case studies of two children with spelling difficulty are reported. LK was multilingual and ED bilingual. A training programme that targeted phonic decoding (or sublexical) spelling processes was conducted with both children. Immediate and delayed post-training assessments showed improvement in spelling nonwords for LK but not for ED. Training that targeted whole word (or lexical) spelling processes was then conducted with ED. Improvement in spelling of irregular words (a marker for lexical spelling processes) was observed. Research into literacy difficulties with multilingual children is sparse, although multilingualism is increasingly widespread. Up to now theoretically based training studies have focused on monolingual children and results were promising. The present findings indicate that theoretically based training programmes for literacy difficulties can also be effective for multilingual children

Genetic Enhancement Perspectives and Prospects for Grain Nutrients Density

Diet-induced micronutrient malnutrition continues to be a major challenge globally, especially in the developing world. With the ever-increasing population, it becomes a daunting task to feed millions of mouths with nutritious food. It is time to reorient agricultural systems to produce quality food to supply the calorie and nutrient requirements needed by the human body. Biofortification is the process of improving micronutrients density by genetic means. It is cheaper and sustainable and complements well with the nutrient supplementation and fortification— the short-term strategies that are currently deployed to address the micronutrient malnutrition. Sorghum is one of the important food crops globally, adapted to semi-arid tropics, and there is increased awareness on its nutritional importance. Further, there is great opportunity to improve sorghum for nutritional quality. This chapter deals about the genetic enhancement perspectives and prospects for improving the nutritional quality with main emphasis on grain micronutrient density in sorghum

THE EFFECT OF THE TYPE OF STERILE CYTOPLASM ON THE PHOTOSYNTHETIC PARAMETERS OF THE GRAIN SORGHUM HYBRIDS

The use of the new types of CMS in the breeding of the heterosis sorghum hybrids needs the study of their effects on the biologic and economic-valuable traits of the plants. During the years of 2010, 2012 and 2013 there were studied the indicators of the photosynthetic potential (PsP) and the net photosynthetic productivity (NPsP) of the grain sorghum hybrids F1 , obtained from two sets of the nuclear CMS-lines with different types of the sterile cytoplasm А3, А4, 9Е (with the genome of the sorghum line ‘Zheltozernoe10’) and М35-1А and 9Е (with the genome of the sorghum line ‘Pishchevoe614’). The grain sorghum varieties ‘Merkuriy’ and ‘Pishchevoe35’ have been used as the pollinators. The indicators of PsP and NPsP have been estimated on the stages ‘sprouts – tillering’, ‘tillering – heading stage’, ‘heading stage – maturity’. It has been determined that the type of the sterile cytoplasm influences upon the PsP and NPsP values of the hybrid F1 . The display of the cytoplasmic differences depends on the environmental conditions and the genotype of the pollinator. On average the hybrids with ‘Merkuriy’ showed significant effects of the type of cytoplasm during all stages of ontogenesis, but the hybrids with ‘Pishchevoe35’ showed the effects only on the stage ‘tillering – heading stage’. The cytoplasm A3 reduced the PsP value of the hybrids, the cytoplasm 9E increased the PsP and NPsP values, especially in the hot and dry environmental conditions. The cytoplasm М35-1А also reduced the PsP value, but significant differences during three years were seen not on all stages of ontogenesis. The obtained data should be taken into account in the programs of the breeding of the heterosis sorghum hybrids