The miR159a-DUO1 module regulates pollen development by modulating auxin biosynthesis and starch metabolism in citrus

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 arrested 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 sequencing (DAP-seq), RNA-seq and verified interaction assays, YUC2/YUC6, SS4, and STP8 were identified as downstream target genes of DUO1 that were all positively regulated by DUO1.