Overexpression of the Ginkgo biloba WD40 gene GbLWD1-like improves salt tolerance in transgenic Populus

WD40 transcription factors are an ancient protein family whose members play important roles in plant growth and stress resistance. In this study, a new WD40 gene was cloned from Ginkgo biloba L. via the rapid amplification of cDNA ends (RACE) technique. This gene was 824 bp in length and encoded 109 amino acids. Sequence alignment and phylogenetic analysis showed that this transcription factor was most similar to the LWD1 protein, and it was thus named GbLWD1-like. This gene was expressed mainly in the leaves, followed by the roots. Phenotypic analysis showed that the transgenic plants grew better, were taller, and had significantly more roots than the control check (CK) plants. Moreover, the transgenic plants were more tolerant to salt stress than the CK plants. After 11 days of salt treatment, all the leaves of the CK plants had dried up and fallen off, whereas in the transgenic lines, only the edges of the bottom leaves had turned yellow. Under salt stress, the expression levels of some genes related to salt tolerance were higher in the transgenic plants than in the CK plants. This study suggests that the GbLWD1-like gene may be related to the growth potential and improved salt tolerance of plants and may play an important role in the response to adversity.