Integrated cyto-physiological and proteomic analyses reveal new insight
into CMS mechanism in a novel upland cotton CMS line LD6A
Cytoplasmic male sterile (CMS) system has extensively been used for
exploiting hybrid vigor in plant breeding programs. However, poor
understanding of molecular mechanism of fertility restoration in CMS is
still a major constraint for its application in many crops. Using
advanced analytical approaches, we elucidated the molecular pathways
regulating CMS induction and fertility restoration in cotton.
Reproductive structures of a novel CMS (LD6A) and its maintainer (LD6B)
line were analyzed physiological and proteomic responses. Significant
differential expression of proteins, such as Abrin, malate
dehydrogenase, malic enzyme, isocitrate dehydrogenase, histone
acetyltransferase was observed in novel CMS and its maintainer line.
Transmission electron micrographs of mitochondrial structure in anther
tapetum showed that the inner ridge of mitochondria in CMS line was
relatively indistinct than that of LD6B with narrower membranous space
at the tetrad stage. Further, relatively higher reactive oxygen species
were accumulated in the anther of CMS than its maintainer line at pollen
mother cell and tetrad stage. We suggest that abnormal sequence of
mitochondrial ribosome gene rps4 and rpl10 and high expression of
ribosome-inactivating protein gene Abrin in CMS line damaged
mitochondrial membrane and consequently induced pollen sterility. These
data provide new insight into CMS mechanism in cotton crops and a tool
to develop new CMS germplasm resources.