Overexpression of the Eggplant (Solanum melongena) NAC Family Transcription Factor SmNAC Suppresses Resistance to Bacterial Wilt.

Bacterial wilt (BW) is a serious disease that affects eggplant (Solanum melongena) production. Although resistance to this disease has been reported, the underlying mechanism is unknown. In this study, we identified a NAC family transcription factor (SmNAC) from eggplant and characterized its expression, its localization at the tissue and subcellular levels, and its role in BW resistance. To this end, transgenic eggplant lines were generated in which the expression of SmNAC was constitutively up regulated or suppressed using RNAi. The results indicated that overexpression of SmNAC decreases resistance to BW. Moreover, SmNAC overexpression resulted in the reduced accumulation of the plant immune signaling molecule salicylic acid (SA) and reduced expression of ICS1 (a gene that encode isochorismate synthase 1, which is involved in SA biosynthesis). We propose that reduced SA content results in increased bacterial wilt susceptibility in the transgenic lines. Our results provide important new insights into the regulatory mechanisms of bacterial wilt resistance in eggplant.

The pTA29-barnase chimeric gene transformation of Brassica campestris L. subsp. chinensis Makino var. parachinensis mediated by agrobacterium / 生物工程学报

In order to induce male sterility of Brassica campestris L. subsp. chinensis Makino var. parachinensis, we introduced the chimeric pTA29-barnase gene into it by Agrobacteriumtume faciens transformation. We obtained the transgenic plants, and determined them by PCR, Southern blotting and RT-PCR analysis. Results indicated that the RNase (barnase) gene had been transferred into genome of plant, and its expression level was different among transformation plants. All transgenic plants were male sterile; there was no vigor or a little pollen without fertility in the anther of transgenic plants. The transgenic plants failed to produce seeds under the condition self-control pollination, but hybrid seeds set were obtained when these transgenic plants were cross-pollinated artificially with normal pollen from untransformed plants. Progeny from cross-pollinated maintainer line with transgenic plants segregated in the 1:1 for male sterility and male fertility, and these phenotypes corresponded directly to the presence or absence of the chimeri TA29-barnase gene. The male fertile plants of co-separated progenies could die by spraying 10 mg/L PPT in cotyledon seedling stage. The hybrid F1 between male sterility and other varieties showed heterosis in yield and growth. All these show that it is an efficient method to induce male sterility in Brassica campestris L. subsp. chinensis Makino var. parachinensis by TA29-barnase ene, there is potential on heterosis breeding of Brassica campestris L. subsp. chinensis Makino var. parachinensis.