Phenotyping Of Some IFox-Hunting Mutants And Preliminary Functional Analysis

Leaves are important organs of plants to communicate with the external environment. Leaf number, morphology, speed of senescence has a degree of influence on development of rapeseed. Previously, we have generated an Arabidopsis mutantion pool that ectopic expressing of Brassica full-length cDNA libraries and have screened out mutants with phenotypes of early senescence and narrow leaf. These two mutants may be useful for providing new insight in developing new varieties of rapeseed. In this study, Bnl327 gene which caused an early senescence in Arabidopsis was transformed by Agrobacterium-mediated genetic transformation into Brassica napus in order to see if the same gene can cause the same phenotype both in Arabidopsis and rapeseed. If this is the case, indicating previously constructed iFOX-Hunting mutation pool can be applied as important platform for functional genomics of rapeseed. Additionally, preliminary functional study of another mutant, rsl-1181, was also performed. The main results are as follows:1. Positive transgenic rapeseed lines transformed with Bnl327 were obtained. Totally, 5 positive transgenic lines of To generation were obtained through Agrobacterium-mediated genetic transformation of Brassica napus hypocotyl. And then Ti seeds were obtained after self-pollination of those 5 positive To transgenic lines.2. To confirm the overexpression of the Bnl327 can caused the same early senescent phenotype in Brassica napus as in Arabidopsis, leaves with the same age from 3-month-old seedlings of Ti and the control plants (W76-1) in the field were detached and treated under dark condition, and the results showed that the leaf senescence of those leaves containing target gene was accelerated, indicating previously constructed iFOX-Hunting mutation pool should be useful platform for functional genomics of Brassica napus.3. Fourteen days after induction, leaves of the mutant rsl-1181 began to become narrow shape in 14 days and became stable in 8 weeks. Leaf length, leaf area of the mutant was significantly smaller than that of wild type plants, and leaf width is very significantly less than that of wild type plants. In addition, phenotype results of statistical analysis indicated the life cycle of this mutant delayed in certain degrees.4. In order to understand the molecular mechanism underneath of the formation of narrow leaves for rsl-1181, couple of genes with high potential of getting involved in the formation of narrow leaves were analyzed with q-PCR according to the model proposed by Dubois et al. Our result was in agreement with that of Dubois’s that ERF6 gene was significantly upregulated, indicating the existing of certain interaction between Bn1181 and ERF6 in controlling the formation of narrow leaves.