Abstract
Achieving seedlessness in citrus varieties is one of the important objectives of citrus breeding.Male sterility associated with abnormal pollen develop-ment is an important factor in seedlessness.How-ever,our understanding of the regulatory mecha-nism underlying the seedlessness phenotype in citrus is still limited.Here,we determined that the miR159a-DUO1 module played an important role in regulating pollen development in citrus,which fur-ther indirectly modulated seed development and fruit size.Both the overexpression of csi-miR159a and the knocking out of DUO1 in Hong Kong kumquat(Fortunella hindsii)resulted in small and seedless fruit phenotypes.Moreover,pollen was severely aborted in both transgenic lines,with ar-rested pollen mitotic I and abnormal pollen starch metabolism.Through additional cross-pollination experiments,DUO1 was proven to be the key target gene for miR159a to regulate male sterility in citrus.Based on DNA affinity purification se-quencing(DAP-seq),RNA-seq,and verified inter-action assays,YUC2/YUC6,SS4 and STP8 were identified as downstream target genes of DUO1,those were all positively regulated by DUO1.In transgenic F.hindsii lines,the miR159a-DUO1 module down-regulated the expression of YUC2I YUC6,which decreased indoleacetic acid(IAA)levels and modulated auxin signaling to repress pollen mitotic I.The miR159a-DUO1 module re-duced the expression of the starch synthesis gene SS4 and sugar transport gene STP8 to disrupt starch metabolism in pollen.Overall,this work re-veals a new mechanism by which the miR159a-DUO1 module regulates pollen development and elucidates the molecular regulatory network un-derlying male sterility in citrus.
基金项目
National Natural Science Foundation of China(NSFC)(32072541)
National Natural Science Foundation of China(NSFC)(31601729)
National Modern Citrus Industry System(CARS-26)
Hubei Province Science and Technology Plan Project(2023BEB025)
Hubei Key Laboratory of Germplasm Innovation and Utilization of Fruit Trees(Institute of Fruit and Tea,Hubei Academy of Agricult(GSSZ202302)
维普
万方数据