Genes Regulating the ABORTED MICROSPORES (AMS)-Mediated Male Sterility Networks in Melon (Cucumis melo L.)

The male sterile plants have higher heterosis in the production of hybrid seeds. The ABORTED MICROSPORES (AMS) gene has been demonstrated to be a candidate gene for ms-5. However, the genetic mechanism underlying AMS-mediated male sterility (MS) regulatory networks in melon (Cucumis melo L.) is still not clearly understood. In the present study, we used transcriptome sequencing analysis, yeast hybridization technology, quantitative real-time polymerase chain reaction (qRT-PCR), and bioinformatics analyzed to systematically investigate the AMS-mediated MS regulatory networks in melon. A set of 15 proteins interacting with AMS, including the C. melo L. Zinc Ribbon protein 1 (CmZR1) gene, was identified using the yeast one-hybrid (Y1H) system and further confirmed using the yeast two-hybrid (Y2H) assay. The interaction of the CmZR1 protein with the C. melo L. Pectin Methylesterase Inhibitor 1 (CmPMEI1) protein was identified and further verified by the glutathione S-transferase (GST) pull-down technique. Bioinformatics analyzed the physical and chemical properties, gene structure, and kinship of the melon PMEI family. We proposed a partial regulatory network for melon MS in which the interaction of CmPMEI1 protein with CmZR1 protein regulates the expression of the AMS gene for pollen abortion. These findings provide important information for increasing the understanding of the molecular mechanism of the MS regulatory network in melon.