Progress on deciphering the molecular aspects of cell-to-cell communication in Brassica self-incompatibility response

Abstract

The sporophytic system of self-incompatibility is a widespread genetic phenomenon in plant species, promoting out-breeding and maintaining genetic diversity. This phenomenon is of commercial importance in hybrid breeding of crops and is controlled by single locus with multiple haplotypes. The molecular genetic studies of '' locus has revealed the presence of three tightly linked loci viz. S-receptor kinase (), S-locus cysteine-rich protein/S-locus protein 11 (/), and S-locus glycoprotein (). On self-pollination, the allele-specific ligand-receptor interaction activates signal transduction in stigma papilla cells and leads to rejection of pollen tube on stigmatic surface. In addition, arm-repeat-containing protein 1 (), M-locus protein kinase (MLPK), kinase-associated protein phosphatase (KAPP), exocyst complex subunit () etc. has been identified in crops and plays a key role in self-incompatibility signaling pathway. Furthermore, the cytoplasmic calcium (Ca) influx in papilla cells also mediates self-incompatibility response in , but how this cytoplasmic Ca influx triggers signal transduction to inhibit pollen hydration is still obscure. There are many other signaling components which are not well characterized yet. Much progress has been made in elucidating the downstream multiple pathways of self-incompatibility response. Hence, in this review, we have made an effort to describe the recent advances made on understanding the molecular aspects of genetic mechanism of self-incompatibility in .

Self-(In)compatibility Systems: Target Traits for Crop-Production, Plant Breeding, and Biotechnology

“…Recent reviews of SI mechanisms provide detailed descriptions of molecular and genetic mechanisms Iwano and Takayama, 2012;Wilkins et al, 2014;Fujii et al, 2016;Bedinger et al, 2017;Sehgal and Singh, 2018;Wang et al, 2018). Here, we provide an overview sufficient for discussing aspects relevant to crop breeding and production.…”

“…In Brassicaceae, S-locus genes encode serine/threonine receptor kinase (SRK) (Takasaki et al, 2000) and cysteine-rich (SP11/SCR) proteins (Schopfer et al, 1999) that, respectively, form the female and male S-determinants. Both S-locus genes, and a third gene encoding a glycoprotein (SLG) that may enhance SI expression (Takasaki et al, 2000), are tightly linked and inherited as an S-haplotype (Sehgal and Singh, 2018). SRK protein is localized to the plasma membrane of the papilla stigmatic cells, and the small SP11 polypeptide is secreted from the anther tapetum, deposited onto the pollen coat, and finally acts as an SRK ligand upon pollination (Iwano and Takayama, 2012).…”

Doubled haploid based parental lines are most suitable in predicting heterosis using microsatellites and in development of highly heterotic F1hybrids inBrassica oleracea

“…It is well established that Brassica vegetables exhibit a wide range of heterosis and high heterosis have been reported in cauliflower also for both yield and quality traits [13, 15, 69]. Nature has bestowed Brassica vegetables with genetic mechanisms of sporophytic self-incompatibility (SI) and cytoplasmic male-sterility (CMS), which have efficiently triggered the hybrid breeding programme in these crops [13, 15, 17, 66, 69, 77]. However, in the current scenario of increasing temperature as a result of global warming there is frequent breakdown of self-incompatibility, as S-alleles are more prone to high temperature.…”

“…However, in the current scenario of increasing temperature as a result of global warming there is frequent breakdown of self-incompatibility, as S-alleles are more prone to high temperature. Thus, SI lines are not always stable and results in sibbed seed in hybrid breeding [66]. In addition, the maintenance of S-allele lines is time consuming and costly endeavor and in case of snowball cauliflower, SI system is very poor or absent [66, 68].…”

“…Thus, SI lines are not always stable and results in sibbed seed in hybrid breeding [66]. In addition, the maintenance of S-allele lines is time consuming and costly endeavor and in case of snowball cauliflower, SI system is very poor or absent [66, 68]. Under these circumstances, the genetic system of CMS provides a better alternative for heterosis breeding in cole crops [17, 69].…”