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光敏核不育水稻(农垦58S)是我国特有的水稻(Oryza sativa L.)种质材料,光敏色素是光周期诱导其育性转变的受体。报道了育性转换敏感期间的光周期处理对农垦58S及对照“农垦58”叶片中光敏色素A(Phy A)含量及其mRNA丰度的影响。在10个光周期处理的最后一个暗期结束前,收获每株水稻的上部两片叶,用酶联免疫吸附测定法测定Phy A。和长日照(LD)相比,短日照(SD)处理导致农垦58SPhy A相对含量增加38.5％;而“农垦58”只增加18.5％。显然,在较长的暗期中,农垦58S中Phy A的积累比对照快。在水稻幼苗中也得出相似的结果。以光敏色素A基因(phy A)的特异性片段RPA3作探针,用RNA斑点杂交的方法对叶片中Phy A mRNA丰度进行分析的结果表明,光周期处理5d和10d时,两品种水稻的Phy A mRNA丰度都是SD处理的比LD的高,而且SD下农垦58S Phy A mRNA的丰度均比“农垦58”的高。这些结果表明,甲基化水平较低的农垦58S phy A可能比“农垦58”的phy A更活跃地表达。另外,在育性转换敏感期每日主光期结束时(EOD)进行10次短暂的远红光(FR)照射。结果表明,农垦58S植株抽穗和开花期比SD处理推迟2d,而花粉败育率、种子结实率却无变化。暗示农垦58S开花和育性转变过程的光周期反应可能不同。
Photosensitive genic male sterile rice (Nongken 58S) is a germplasm material of rice (Oryza sativa L.) that is peculiar to China. Phytochrome is a photoreceptor which induces its fertility transformation through photoperiod. The effects of photoperiod treatments on the content and mRNA abundance of PhyA in Nongken 58S and Nongken 58 were reported. Before the end of the last dark period of 10 photoperiod treatments, the upper two leaves of each rice crop were harvested and PhyA was determined by enzyme-linked immunosorbent assay. Short-day (SD) treatment resulted in a 38.5% increase in the relative content of NSPH 58SPhy A compared to long-day (LD), whereas Nongken 58 increased only 18.5%. Obviously, PhyA accumulation was faster in the Nongken 58S than in the control during the longer dark period. Similar results have also been obtained in rice seedlings. PhyA phylogenetic tree was used to probe PhyA mRNA abundance in the leaves by RNA dot blotting. The results showed that the photosynthetic rate PhyA mRNA abundance was higher in SD than LD, and the abundance of 58S Phy A mRNA in Nongken was higher than that in Nongken 58. These results indicate that Nongken 58S phy A with lower methylation level may be more actively expressed than phyA N at “Nongken 58”. In addition, 10 short-term far-red (FR) exposures were made at the end of the main photoperiod (EOD) in the fertility-sensitive period. The results showed that the heading and flowering stages of Nongken 58S were delayed 2 days than that of SD treatment, while the pollen abortion rate and seed setting rate did not change. Suggesting that the photoperiodic response of Nongken 58S during flowering and fertility transformation may be different.