Cloning and characterization of a gene encoding novel zinc finger protein transcription factor induced under water deficit stress from rice (Oryza sativa) cv. N-22.

A gene OsZnI encoding Cys3/His1-type zinc finger protein was isolated from the water stress-induced cDNA library of rice (Oryza sativa) cv. N-22, an early maturing, deep-rooted, drought-tolerant genotype adapted to upland conditions. The in-silico analysis revealed an insert of 800 bp with an ORF of 663 nucleotides, encoding 221 amino acids. OsZnI had three distinct features — nuclear localization signal (NLS) present in Arg152-Arg168, Zn finger domain between 185-193 amino acids and 12 amino acids conserved domain in 71-82 amino acids homologous to LEA motif, and belonged to C-type family of Zn finger protein. OsZnI showed induced expression under water deficit stress.

Transgenic tobacco plants expressing BoRS1 gene from Brassica oleracea var. acephala show enhanced tolerance to water stress.

Water stress is by far the leading environmental stress limiting crop yields worldwide. Genetic engineering techniques hold great promise for developing crop cultivars with high tolerance to water stress. In this study, the Brassica oleracea var. acephala BoRS1 gene was transferred into tobacco through Agrobacterium-mediated leaf disc transformation. The transgenic status and transgene expression of the transgenic plants was confirmed by polymerase chain reaction (PCR) analysis, Southern hybridization and semi-quantitative one step RT-PCR analysis respectively. Subsequently, the growth status under water stress, and physiological responses to water stress of transgenic tobacco were studied. The results showed that the transgenic plants exhibited better growth status under water stress condition compared to the untransformed control plants. In physiological assessment of water tolerance, transgenic plants showed more dry matter accumulation and maintained significantly higher levels of leaf chlorophyll content along with increasing levels of water stress than the untransformed control plants. This study shows that BoRS1 is a candidate gene in the engineering of crops for enhanced water stress tolerance.

Expression profiles of hot pepper (Capsicum annum) genes under cold stress conditions.

In an attempt to determine a cold defense mechanism in plants, we have attempted to characterize changes occurring in the expression of cold-regulated transcript levels in the hot pepper (Capsicum annum), using cDNA microarray analysis, combined with Northern blot analysis. After analysing a 3.1 K hot pepper cDNA microarray, we isolated a total of 317 cold inducible genes. We selected 42 genes which were up-regulated and three genes which were down-regulated due to cold treatment, for further analysis. Among the 45 genes which appeared to be up-regulated by cold, 19 genes appeared to be simultaneously regulated by salt stress. Among the up-regulated cold-stress genes, we identified a variety of transcription factors, including: a family of 4 ethylene-responsive element binding protein (EREBP, designated CaEREBP-C1 to C4) genes, a bZIP protein (CaBZ1), RVA1, Ring domain protein, HSF1, and the WRKY (CaWRKY1) protein. As mentioned earlier, several genes appeared to be induced not only by cold stress, but also simultaneously by salt stress. These genes included: CaEREBP-C3, CaBZ1, putative trans-activator factor, NtPRp27, malate dehydrogenase, putative auxin-repressed protein, protein phosphatase (CaTPP1), SAR8.2 protein precursor, late-embryogenesis abundant protein 5 (LEA5), DNAJ protein homologue, xyloglucanendo-1,4-beta-D-gucanase precursor, PR10, and the putative non-specific lipid transfer protein StnsLTP.