延缓衰老基因PPF1转化水稻的初步研究

Preliminary Study on Introducing of Leaf Senescence-Delaying Gene PPF1 into Rice

利用农杆菌介导法,把短日豌豆花后特异表达、具有延缓衰老作用的基因PPF1(post-floral-specificgeneexpressedinshort-day-grownG2pea)转入水稻,以期获得延缓衰老的转基因植株。约970块未成熟胚性愈伤组织与农杆菌共培养后,得到了约280块抗性愈伤组织,从中分化出抗性绿苗54株。PCR和Southernblotting检测结果表明,外源基因已经插入受体基因组,其中42株含有目的基因,阳性率为77.7%。部分阳性植株分析表明,多数转基因植株的叶绿素含量和光合指标显著高于对照。衰老进程研究证实,转基因植株的叶片衰老表现一定程度的延迟。说明PPF1基因在植株内得到了表达,并具一定延缓衰老的作用。

Premature senescence of leaf, usually results in too much abortive grains and lowing in seed-setting-rate, is a common problem for many plants and always led to great loss of production. In this study, the leaf senescence-delaying gene, PPF1, a post-floral-specific gene expressed in short-day-grown G2 pea, was introduced into rice to delay the progress of leaf senescence by the approach of Agrobacterium-mediated transformation. After the co-cultivation of over 970 seutellum calli with Agrobacterium tumefaciens, about 280 hygromycin-resistant calli were obtained, and 54 independent plantlets derived from different calli were regenerated from them（Table 1）. The results from PCR （Fig.2, 3） and Southern blotting （Fig.4） demonstrated that the target gene was integrated into the genome of 42 plantlets with a positive ratio of 77.7%. The chlorophyll content, photosynthetic index and leaf senescence in To transgenic plants were also discussed. The results indicated that most of the transgenic plants were remarkably higher than the control both in the chlorophyll content（Fig. 5）and photosynthetic index （Fig. 6）, and as a result, the leaf senescence process in the transgenic plants was obviously inhibited（Table 2） . It suggested that PPF1 gene might express in the transgenic plants, and the leaf senescence was delayed, which may show a new way to improve the rice production.