A functional characterization of TaMs1 orthologs in Poaceae plants

TaMs1 encodes a non-specific lipid transfer protein(nsLTP) and is required for pollen development in wheat. Although MS1 is a Poaceae-specific gene, the roles of MS1 genes in other Poaceae plants are unknown, especially in rice and maize. Here, we identified one ortholog in rice(OsLTPg29) and two orthologs in maize(ZmLTPg11 and ZmLTPx2). Similar to TaMs1, both OsLTPg29 and ZmLTPg11 genes are specifically expressed in the microsporocytes, and both OsLTPg29 and ZmLTPg11 proteins showed lipid-binding ability to phosphatidic acid and several phosphoinositides. To determine their roles in pollen development, we created osltpg29 mutants and zmltpg11 zmltpx2 double mutants by CRISPR/Cas9.osltpg29, not zmltpg11 zmltpx2, is defective in pollen development, and only OsLTPg29, not ZmLTPg11,can rescue the male sterility of tams1 mutant. Our results demonstrate that the biological function of MS1 in pollen development differs in the evolution of Poaceae plants.

GDSL esterase/lipases OsGELP34 and OsGELP110/OsGELP115 are essential for rice pollen development

Pollen exine contains complex biopolymers of aliphatic lipids and phenolics.Abnormal development of pollen exine often leads to plant sterility.Molecular mechanisms regulating exine formation have been studied extensively but remain ambiguous.Here we report the analyses of three GDSL esterase/lipase protein genes,OsGELP34,OsGELP110,and OsGELP115,for rice exine for-mation.OsGELP34 was identified by cloning of a male sterile mutant gene.OsGELP34 encodes an endoplasmic reticulum protein and was mainly expressed in anthers during pollen exine formation.osgelp34 mutant displayed abnormal exine and altered expression of a number of key genes required for pollen development.OsGELP110 was previously identified as a gene differentially expressed in meiotic anthers.OsGELP110 was most homologous to OsGELP115,and the two genes showed similar gene expression patterns.Both OsGELP110 and OsGELP115 proteins were localized in peroxisomes.Individual knockout of OsGELP110 and OsGELP115 did not affect the plant fertility,but double knockout of both genes altered the exine structure and rendered the plant male sterile.OsGELP34 is distant from OsGELP110 and OsGELP115 in sequence,and osgelp34 and osgelp110/osgelp115 mutants were different in anther morphology despite both were male sterile.These results suggested that OsGELP34 and OsGELP110/OsGELP115 catalyze different compounds for pollen exine development.

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

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.

水稻雄性不育突变体ms102的鉴定和基因定位

水稻(Oryza sativa)隐性核雄性不育突变体是第三代杂交水稻技术的核心。为了挖掘优质雄性不育突变体,该研究通过筛选优质籼稻黄华占(HHZ)的甲基磺酸乙酯(EMS)诱变突变体库,获得1个雄性不育突变体ms102(male sterility mutant 102)。该突变体营养生长正常,但花药不开裂,花粉败育。细胞学分析表明,突变体花药绒毡层不能正常降解,导致小孢子发育异常;遗传分析表明,该突变体的不育表型由1个已报道编码酰基转移酶的DPW2基因突变造成。研究获得了1个隐性核雄性不育突变体,进一步证实了DPW2基因在水稻花药发育中的功能。