An ms2 male‐sterile, female‐fertile soybean sharing phenotypic expression with other ms mutants

Abstract

Genetic and cytological studies of microsporogenesis and microgametogenesis were conducted with a natural male-sterile, female-fertile soybean mutant (BR97-17971) found in an F 4 breeding line of the Brazilian soybean breeding programme. Allele tests with ms Type Collection from USDA/ARS showed that the gene was allelic to ms2. Conventional analysis of microsporogenesis revealed a differential meiotic behaviour from the normal one reported in ms2 male-sterile plants. Sterile plants have different levels of meiotic abnormalities related to chromosome segregation. Despite segregational abnormalities in the first and second divisions leading to micronuclei formation, the main meiotic cause of pollen sterility was absent or the defective cytokinesis following telophase II. Absent or defective cytokinesis has never been reported in ms2 mutants, but it was reported in the ms1 and ms4 mutants. After telophase II, one to four nucleate microspores underwent degeneration. Cross-sections of sterile plant anthers showed that, at telophase II, the tapetal cells with large vacuoles degenerated. Despite callose deposition around meiocytes, sterile plants did not form tetrads. They degenerated and collapsed after callose dissolution, forming an amorphous mass. Anthers from male-sterile plants were shrivelled.

Meiotic behavior in wild and domesticated species of Passiflora

“…The fertility of an individual depends, in large part, on meiotic regularity, and some genes which affect meiosis have already been described (Gottschalk & Kaul 1980, Bione et al 2002, Li et al 2003. If the events that occurred during meiosis are under genetic control, they are mutable (Defani-Scoarize et al 1996), causing some irregularities such as laggard chromosomes (Consolaro & Pagliarini 1996) and spindle orientation abnormalities (Tilquin et al 1984, Caetano-Pereira et al 1998.…”

Isolation of genes from female sterile flowers in Medicago sativa

“…Beta 1-3 glucanases break down callose and can be organ-specific (Lotan et al 1989;Del Campillo and Lewis 1992). In situ hybridization confirmed the abundance of transcript in the (Smyth et al 1990;Castresana et al 1990), and callose accumulation has been considered a consequence, not a cause, of sterility (Bione et al 2002). However, in female sterile alfalfa, callose accumulation takes place at the same time, or even before the block of meiosis, opening the possibility that defects in callose metabolism may be a cause of sterility.…”

Cytological Investigations of the Microsporogenesis in Male-sterile Ramie (Boehmeria nivea Gaud.) and Its Offspring

“…Association of male sterility with some meiotic abnormalities such as chromosome stickiness and/or laggard chromosomes have been reported in some wild or cultivated plants as Capsicum annuum (Chhibber et al 2007), soybean (Bione et al 2002) and Withania somnifera (Iqbal and Datta 2008 27 Microsporogenesis in male-sterile ramie 2007), for instance. However, in ramie both types of abnormalities were observed not only in malesterile but also in male-fertile plants.…”