The Study On Biological Function Of AP2/EREBP Transcription Factors In Rice

The AP2/EREBP transcription factors play roles in floral development of andthe resposnses of plants to adverse stresses, and they are divided into AP2 subfamily withtwo AP2 domains and EREBP subfamily with single AP2 domain. AP2 subfamilyparticipated in flower development procession, including the establishment of floralmeristem identity, the specification of flower organ identity and the regulation of floralorganogenesis, the temporal and spatial regulation of flower homeotic gene activity, and itexpresses in flower organ. Members of EREBP subfamily are known to function inresponding to biotic and abiotic stresses, such as ethylene, salt, low-temperature anddrought, thus conferring resistance of plants against adverse environment. OsEBP-89 isfirstly separated known as an EREBP transcription factor in a monocotyledonous plant.There are quite a number of AP2 family genes in rice,except OsERP-89 gene. Here wecloned two EREBP-like gene in rice, W195 and W192. The deduced proteins (W195 andW192) contain RAYD and YRG elements conserved in other known DREBPs. W195 andW192 are single-copy genes in rice genome with W195 localizing in chromosome 8 andW192 in chromosome 4. To further study the function of them, RNAi and over-expressionvectors were constructed for each gene, then they are separately transformed into rice byan agrobacterium-mediated method. The transgenic rices of W195RNAi and W192RNAiare confirmed by PCR. Some of transgenic plants are dwarf, and their setting rates werereduced. All these phenotypes suggest that their endogenous expression was knock-downby each cooresponding RNAi construct , thereby affecting the growth of reproductiveand vegetative development of these transgenic plants. Furthermore, nucleus-localizing ofW195 protein suggest that W195 functions in nucleolus.