Lectin receptor kinase OsLecRK‐S.7 is required for pollen development and male fertility

Abstract

Pollen grains are covered by exine that protects the pollen from stress and facilitates pollination. Here we isolated a male sterile mutant s13283 in rice exhibiting aborted pollen with abnormal exine and defective aperture. The mutant gene encodes a novel plasma membrane‐localized legume‐lectin receptor kinase that we named OsLecRK‐S.7. OsLecRK‐S.7 was expressed at different levels in all tested tissues and throughout anther development. In vitro kinase assay showed OsLecRK‐S.7 capable of autophosporylation. Mutation in s13283 (E560K) and mutation of the conserved ATP binding site (K418E) both knocked out the kinase activity. Mass spectrometry showed Thr376, Ser378, Thr386, Thr403, and Thr657 to be the autophosphorylation sites. Mutation of individual autophosphorylation site affected the in vitro kinase activity to different degrees, but did not abolish the gene function in fertility complementation. oslecrk‐s.7 mutant plant overexpressing OsLecRK‐S.7 recovered male fertility but showed severe growth retardation with reduced number of tillers, and these phenotypes were abolished by E560K or K418E mutation. The results indicated that OsLecRK‐S.7 was a key regulator of pollen development.

Genome-wide analysis of proline-rich extension-like receptor protein kinase (PERK) in Brassica rapa and its association with the pollen development

“…their extracellular domain motifs [6,7]. For instance, the leucine-rich repeat receptor kinases (LRR-RKs) are the largest of the RK family in Arabidopsis and sense a diverse set of hormone signaling pathways to regulate cell proliferation and expansion, stomatal development and stem cell maintenance [5,[8][9][10].…”

An L-type lectin receptor-like kinase promotes starch accumulation during rice pollen maturation

“…However, other sporophytic cellular defects among these allelic mutants were highly variable. For example, the pollen exine was thickened in s13283 grains (Peng et al, 2019), while the ap1 (Fig. 6, Fig.…”

“…It is possible that the sporophytic defects of ap1 cannot be seen, but are sufficient to alter fertility. Very recently, three other allelic mutants of AP1 were reported: s13283 (in the background of the indica cultivar Huanghuazhan), oslecrk5 (in the background of the japonica cultivar 02428) and defective in aperture formation1 (osdaf1; in the background of the japonica cultivar 9522) (Peng et al, 2019;Wang et al, 2020;Zhang et al, 2020). We carefully compared the cytological characteristics of these allelic mutants and found that they all showed the following identical features: shrinking pollen grains with gametophytic defects (less or no cellular content and absence of pollen intine layer) and sporophytic defects (abnormal aperture morphology).…”

Lectin Receptor-Like Kinases: The Sensor and Mediator at the Plant Cell Surface

“…Two other LecRLKs, OsSIK2 in rice and GsSRK in soybean can both be induced by ABA treatment and contribute to plant architecture, while the former also delays dark-induced senescence in rice Sun et al, 2018). Moreover, OsLecRK-S.7 in rice and LecRK-IV.2 in Arabidopsis are required for pollen development and the former is also responsible for male fertility (Wan et al, 2008;Peng et al, 2019). Although most of these findings on the involvement of LecRLKs in plant development still need further investigation to provide a clear picture, one clue is that plant hormones, especially ABA and GA, are in close association with the function of LecRLKs in plant growth and development.…”