Developmental Localization and Methylesterification of Pectin Epitopes during Somatic Embryogenesis of Banana (Musa spp. AAA)

The plant cell walls play an important role in somatic embryogenesis and plant development. Pectins are major chemical components of primary cell walls while homogalacturonan (HG) is the most abundant pectin polysaccharide. Developmental regulation of HG methyl-esterification degree is important for cell adhesion, division and expansion, and in general for proper organ and plant development.Developmental localization of pectic homogalacturonan (HG) epitopes and the (1→4)-β-D-galactan epitope of rhamnogalacturonan I (RG-I) and degree of pectin methyl-esterification (DM) were studied during somatic embryogenesis of banana (Musa spp. AAA). Histological analysis documented all major developmental stages including embryogenic cells (ECs), pre-globular, globular, pear-shaped and cotyledonary somatic embryos. Histochemical staining of extracellularly secreted pectins with ruthenium red showed the most intense staining at the surface of pre-globular, globular and pear-shaped somatic embryos. Biochemical analysis revealed developmental regulation of galacturonic acid content and DM in diverse embryogenic stages. Immunodots and immunolabeling on tissue sections revealed developmental regulation of highly methyl-esterified HG epitopes recognized by JIM7 and LM20 antibodies during somatic embryogenesis. Cell walls of pre-globular/globular and late-stage embryos contained both low methyl-esterified HG epitopes as well as partially and highly methyl-esterified ones. Extracellular matrix which covered surface of early developing embryos contained pectin epitopes recognized by 2F4, LM18, JIM5, JIM7 and LM5 antibodies. De-esterification of cell wall pectins by NaOH caused a decrease or an elimination of immunolabeling in the case of highly methyl-esterified HG epitopes. However, immunolabeling of some low methyl-esterified epitopes appeared stronger after this base treatment.These data suggest that both low- and highly-methyl-esterified HG epitopes are developmentally regulated in diverse embryogenic stages during somatic embryogenesis. This study provides new information about pectin composition, HG methyl-esterification and developmental localization of pectin epitopes during somatic embryogenesis of banana

Culture de suspensions cellulaires embryogéniques et régénération en plantules par embryogenèse somatique chez le bananier et le bananier plantain Musa spp

Embryogenie cell suspension and plant regeneration through somatic embryogenesis in bananas and plantains Musa spp. Embryogenie cell suspensions have been initiated using explants from meristematic shoot-tips (scalps). The culture medium has been a modified Murashige and Skoog medium supplemented, according to the steps of culture, with 5fiM 2, 4-D, 1-10//M BAPorzeatin. The suspensions obtained for 5 banana varieties have regenerated plants through somatic embryogenesis. Embryogenie cell suspensions have proved to be the material of choice for cryopreservation, protoplast isolation and culture and for genetic manipulation of Musa for resistance to diseases

Agrosystems and Mycorrhizae of Plantain (Musa AAB subgroup) in the Forest Region of Kisangani in DR Congo: Abundance and Diversity

Although DR Congo is the global centre of plantain diversity (Musa, AAB subgroup), the arbuscular mycorrhizal fungi (AMF) associated with plantain have not yet been studied in the forest region of Kisangani. This study assessed the abundance and the diversity of AMF in plantain cultivated in different agrosystems. The study addressed also the relation between AMF diversity and plantain vigour as well as the impact of soil characteristics on AMF population. Soil samples were collected from 24 plantain fields from secondary forest, fallow and homegardens. Plantains from fallow exhibited the highest mycorrhizal root colonization followed by those from forest and homegardens. But, the rhizosphere of plantains in forest had a higher amount of AMF spores than those located in fallow and in homegarden. The mycorrhizal root colonization and the AMF spore number were higher in vigorously growing plantain plants than in non-vigorously growing plantain plants. Gigasporaceae (20.4 %) has a positive correlation with plantain fields in forest and in homegardens with a strong link to organic matter, organic carbon, phosphorus and sand content. Glomeraceae (77.5%) was related to plantain fields located in fallow and in forest where the level of silt, nitrogen and hydraulic conductivity was high. Acaulosporaceae (2.1%) did not show any particular correlation with any soil parameters. This study shows that plantain located in forest and fallow agrosystems, and plantain growing vigorously harbour most mycorrhizae in the forest region of Kisangani . Keywords: Agrosystem, AMF, Kisangani, plantai

Plantain diversity in the Democratic Republic of Congo and future prospects

© 2018 International Society for Horticultural Science. All rights reserved. The Democratic Republic of Congo (DR Congo) is the largest centre of diversity for plantain (Musa AAB subgroup). In the the 1940s and 1950s descriptions of a collection of 56 accessions at Yangambi (INERA ex INEAC) were published. Between 2005 and 2015, new collection missions covering 306 villages of DR Congo gave morphological descriptors of 107 cultivars, which were established in two fields at the University of Kisangani (UNIKIS). Ninety-seven of these cultivars are completely characterized and grouped into French (64 accessions), False Horn (23 accessions) and Horn (10 accessions) types. Three plant size categories were distinct in the French plantain accessions (24 giant, 22 medium and 12 small) but less obvious within the False Horn and Horn accessions. A similar proportion between the three bunch types was found for dwarfism. The dominant bunch orientation was pendulous (71% of all accessions). Different colours of pseudostem (green, dark green, mottled red and black) and of immature fruit peel (brown, dark green, green, red and yellow) were recorded, green being predominant. The collected cultivars will be further characterized for their agronomic and postharvest performance, used in breeding and characterized at the molecular level.status: publishe

The morphological diversity of plantain in the Democratic Republic of Congo

© 2018 Elsevier B.V. This work focused on the morphological characterization of plantain cultivars collected in the period 2005–2014 in 280 villages across 9 provinces of the Democratic Republic of Congo. These cultivars were established in two field collections at the University of Kisangani.Existing descriptors were adapted to better differentiate their variation to address better the taxonomic handicap and the synonymy handicap to improve future research on plantains.Most of the collected cultivars were French plantains (64 out of 98), followed by False Horn (23) and Horn (10) plantains. The bunch type was the main striking difference which allows the quick separation of plantain cultivars into three main types. Other striking differences within plantain were the size of the pseudostem (giant, medium-sized and small-sized) and the bunch orientation (which was generally pendulous or sub-horizontal, and rarely horizontal and erect). These three descriptors were considered as main descriptors. Other descriptors (pseudostem colour, immature fruit peel colour, fruit shape, fruit apex, fruit position, number of hands, fruit size, number of fingers per hand and flower relicts at the fruit apex) allowed the differentiation of one cultivar from another within the same main group of bunch type, pseudostem size or bunch orientation. These descriptors are considered as secondary descriptors. Rare descriptors allowed to differentiate one cultivar from all the others in the subgroup. This approach makes the cultivar description logical and faster because it moves from general to particular characteristics, and it offers a platform for reflections on the Pan-African scale of plantain diversitystatus: publishe

The complex distribution of plantain cultivars (Musa sp., AAB subgroup) in the Bas-Uele province of the Democratic Republic of Congo

status: publishe

Influence of agrosystems on the diversity of mycorrhizae under plantain banana cultivation in the forest region of Kisangani (Tshopo Province, DR Congo)

Open Access Article; Published online: 18 May 2022The largest genetic diversity of plantain banana (Musa AAB subgroup) is found by DRCongo. Arbuscular mycorrhizal fungi (AMF) are synergistic beneficial organisms with a positive effect on growth vigor. We determined the influence of plantain banana-based agrosystems on the diversity of AMF in agroforestry and home-garden field systems located in the Kisangani region of DR Congo. Soil samples of the different agrosystems showed a high mycorrhizal frequency (82.5%) with an overall mycorrhizal rate of 33.43%. Vigorous plantain plants are growing in soils that rich in AMF spores whereas non vigorous ones were found in soils that had few AMF spores. There were also significant differences between cultivars, in terms of the number of spores. Glomus was the most abundant genus followed by Gigaspora, Acaulospora, Scutellospora and Entrophospora. The diversity indices evaluated, richness, abundance and Shannon_H showed non-significant difference between agroforestry and home-garden plantains. However, agroforestry plantains showed a larger Inv-Simpson and Equitability-J index than home-garden plantains. Soil physico-chemical characteristics had an effect on abundance of mycorrhizal genera in all inventoried mycorrhizal taxa