Agrobacterium-mediated Transformation With Fc17178and FcWRKY70Genes In Citrus And Resistance Evaluation Of The Transgenic Plants

Citrus is one of the most cultivated and economically important fruit trees in southern China. However, the sustainability of the citrus industry is constantly challenged by drought and salt stresses, making the creation of new cultivars resistant to these abiotic stresses an urgent issue. In this study, two genes, Fc17178and FcWRKY70of Fortunella japonica Swingle, were introduced into Poncirus (Poncirus trifoliata L. Raf.) and lemon(Citrus limon Burm.f.) via Agrobacterium-mediated transformation to check their roles in improving the drought and salt resistance of plants. The main results are as follows:1. Eight positive transgenic plants overexpressing Fc17178were identified by PCR amplification in trifoliate orange. The semi-quantitative RT-PCR results showed that the expression of Fcl7178was high in two transgenic lines,#1and#4. After200mM NaCl treatment, compared with the WT plants, the transgenic lines showed significantly less serious leaf burning and defoliation, along with lower MDA accumulation, and higher chlorophyll contents. After NaCl treatment,the transgenic plants accumulated lower levels of Na+, concurrent with increased level of K+, leading to a higher K+/Na+ratio.2. FcWRKY70was introduced into lemon by Agrobacterium-mediated transformation; thirty-three positive transgenic plants were identified by PCR Amplification. Real-time PCR analysis indicates that the expression level of FcWRKY70was significantly higher in the transgenic lines(#28,#33and#43) than that in the WT. Dehydration treatment revealed that two transgenic lines (#28and#43) exhibited lower relative water loss rate and higher drought resistant ability than WT.NBT staining showed that the accumulation of superoxide anion in the transgenic plants was less than WT, demonstated the transgenic plants were improved the salt resistance...