Molecular characters and different expression of WRKY1 gene from Gossypium barbadense L. and Gossypium hirsutum L.

Abstract

Cotton is one of the most important economic crops in the world. Gossypium barbadense L. has higher resistance to Verticillium wilt than Gossypium hirsutum L. In the present study, seedlings of Pima90-53 (G. barbadense) had better growth performance than those of CRI8 (G. hirsutum) inoculated with Verticillium dahliae. WRKY1 genomic DNA of Pima90-53 and CRI8 were isolated (GbWRKY1 and GhWRKY1) and predicted to include three introns which were 289, 92, 87 bp and 286, 92, 87 bp in length, respectively. Compared with the DNA sequence of GbWRKY1, GhWRKY1 had a 13-base deletion in exon 4, which resulted in premature termination of translation. It was predicted that the GbWRKY1 and GhWRKY1 proteins contain two WRKY domains and zinc-finger motifs belonging to group I WRKY proteins. Two promoters, located 1745 bp and 1738 bp upstream of GbWRKY1 and GhWRKY1, were cloned and predicted to contain important regulatory elements (TATA-box, CAAT-box and pathogen/elicitor-related elements). Interestingly, compared with GbWRKY1, the GhWRKY1 promoter lacked an ethylene-responsive element (ERE) component. The relative expression of GbWRKY1, too, was higher than that of GhWRKY1 after V. dahliae and ACC (1-aminocyclopropane-1-carboxylic acid) induction. The results suggest that the difference in the promoter sequence could probably be one of the reasons that lead to different expression patterns and resistance to Verticillium wilt in Pima90-53 and CRI8.

Ex vitro hairy root induction in detached peanut leaves for plant–nematode interaction studies

“…Herein, the ex vitro petiole transformation efficiency obtained was similar to those observed under in vitro conditions (91%) [19]. It is worth noting that the competence of these explants to differentiate into hairy roots seems to be dependent on the peanut varietal-group (Runner, Virginia, Valencia or Spanish) [7, 39].…”

“…Diverse types of peanut explants have been tested for A. rhizogenes transformation, such as petioles, epicotyls, embryonic axes, hypocotyls, and leaves, which showed different transformation efficiencies, from 14 to 91%, depending on the explant and host genotype [15–19]. Herein, the ex vitro petiole transformation efficiency obtained was similar to those observed under in vitro conditions (91%) [19].…”

“…Although other pathogenic wild (ATCC 15834, A4, MAFF-02-10266) and engineered (R1000, R1601, R1200) strains had also been employed to induce hairy roots in peanut [15, 17, 19, 49, 50], only the ‘K599’ wild strain was successfully used for studies on peanut–RKN interaction [17]. The A. rhizogenes strain type is strongly associated with the undesirable morphological variability of hairy roots, which comprises one of the main constraints to its use for functional gene studies.…”

“…Therefore, peanut hairy roots, as composite plants or cultivated in vitro, have been successfully applied to study genes involved in nodule formation and nitrogen fixation [15, 16], nematode interaction [17], subterranean insects [18], and drought tolerance [19]. The recent availability of peanut progenitors’ whole genomes ( A. duranensis and A. ipaënsis ) [3, 20], coupled with transcriptome surveys of wild species ( A. stenosperma, A. magna, A. diogoi, and A. duranensis ) [9, 21–23], has substantially raised the number of candidate genes involved in tolerance/resistance to abiotic and biotic stresses.…”

Identification of lipoxygenase (LOX) genes from legumes and their responses in wild type and cultivated peanut upon Aspergillus flavus infection

“…Liu, et al . 47 found the expression level of Gossypium barbadense WRKY1 is higher than that in Gossypium hirsutum WRKY1 after Verticillium dahliae infection, and the GhWRKY1 promoter lacks an ethylene-responsive element compared to the GBWRKY1 promoter, indicating promoter differences probably resulted in differences in expression patterns. Understanding the expression regulation of disease-resistance genes in tetraploid peanut may facilitate the development of an efficient method to improve disease resistance in cultivated peanut.…”