Self-incompatibility(SI)substantially restricts the yield and quality of citrus.Therefore,breeding and analyzing selfcompatible germplasm is of great theoretical and practical signi ficance for citrus.Here,we focus on...Self-incompatibility(SI)substantially restricts the yield and quality of citrus.Therefore,breeding and analyzing selfcompatible germplasm is of great theoretical and practical signi ficance for citrus.Here,we focus on the mechanism of a self-compatibility mutation in‘Guiyou No.1'pummelo(Citrus maxima),which is a spontaneous mutant of‘Shatian’pummelo(Citrus maxima,self-incompatibility).The rate of fruit set and the growth of pollen tubes in the pistil con firmed that a spontaneous mutation in the pistil is responsible for the self-compatibility of‘Guiyou No.1'.Segregation ratios of the S genotype in progeny,expression analysis,and western blotting validated that the reduced levels of S_(2)-RNase mRNA contribute to the loss of SI in‘Guiyou No.1'.Furthermore,we report a phased assembly of the‘Guiyou No.1'pummelo genome and obtained two complete and well-annotated S haplotypes.Coupled with an analysis of SV variations,methylation levels,and gene expression,we identi fied a candidate gene(CgHB40),that may in fluence the regulation of the S/^RNase promoter.Our data provide evidence that a mutation that affects the pistilled to the loss of SI in‘Guiyou No.1'by in fluencing a poorly understood mechanism that affects transcriptional regulation.This work signi ficantly advances our understanding of the genetic basis of the SI system in citrus and provides information on the regulation of S-RNase genes.展开更多
基金This research was financially supported by the National Key Research and Development Program of China(grant no.2018YFD1000107)the National Natural Science Foundation of China(grant nos.31772259,31630065,and 31521092)+1 种基金the Fundamental Research Funds forthe Central Univer sities(grant no.2662019PY044)the China Agriculture Research System of MOF and MARA and the Hubei Provincial Natural Science Foundation of China(2020CFB532).
文摘Self-incompatibility(SI)substantially restricts the yield and quality of citrus.Therefore,breeding and analyzing selfcompatible germplasm is of great theoretical and practical signi ficance for citrus.Here,we focus on the mechanism of a self-compatibility mutation in‘Guiyou No.1'pummelo(Citrus maxima),which is a spontaneous mutant of‘Shatian’pummelo(Citrus maxima,self-incompatibility).The rate of fruit set and the growth of pollen tubes in the pistil con firmed that a spontaneous mutation in the pistil is responsible for the self-compatibility of‘Guiyou No.1'.Segregation ratios of the S genotype in progeny,expression analysis,and western blotting validated that the reduced levels of S_(2)-RNase mRNA contribute to the loss of SI in‘Guiyou No.1'.Furthermore,we report a phased assembly of the‘Guiyou No.1'pummelo genome and obtained two complete and well-annotated S haplotypes.Coupled with an analysis of SV variations,methylation levels,and gene expression,we identi fied a candidate gene(CgHB40),that may in fluence the regulation of the S/^RNase promoter.Our data provide evidence that a mutation that affects the pistilled to the loss of SI in‘Guiyou No.1'by in fluencing a poorly understood mechanism that affects transcriptional regulation.This work signi ficantly advances our understanding of the genetic basis of the SI system in citrus and provides information on the regulation of S-RNase genes.
