Down-regulation of the OsPDCD5 gene induced photoperiod-sensitive male sterility in rice

Programmed cell death (PCD) is a crucial process for plants during development and environmental stress. OsPDCD5, is an ortholog to mammalian programmed cell death 5 gene. Here we report that decreased expression of OsPDCD5 caused by antisense technology could induce pollen sterility in photoperiod-sensitive rice. The male sterility of transgenic plants is reversible, determined mainly by photoperiod. Transgenic plants are sterile under long-day photoperiod (≥13.5 h sunlight) with postponed heading time, while they can restore fertility under short-day photoperiod (below 13 h sunlight). Analysis of tissue sections of anthers displays the tapetum cells of the anther wall retard PCD process in transgenic plants under long-day photoperiod. The retarded PCD was also confirmed by DNA fragmentation. In F1 hybrids made from transgenic plants with antisense-OsPDCD5 and japonica rice varieties, lower transcript inhibition could restore fertility, under certain photoperiod and temperatures. The surprising discovery of the photosensitive male fertility suggested that by using specific photoperiods, the male sterility (PGMS) could be used for commercial production of hybrid rice using a two-line breeding system. The transgenic hybrid strategy was easy to apply, reduced costs and shortened the breeding period. It provides great advantages for commercial applications in rice and other crops.