Expansins, cell-wall loosening proteins, play an important role in plant growth and development and abiotic stress tolerance. Ammopiptanthus nanus (A. nanus) is an important plant to study to understand stress resistance in forestry. In our previous study, two α-type expansins from A. nanus were cloned and named AnEXPA1 and AnEXPA2. In this study, we found that they responded to different abiotic stress and hormone signals. It suggests that they may play different roles in response to abiotic stress. Their promoters show some of the same element responses to abiotic stress and hormones, but some special elements were identified between the expansins that could be essential for their expression. In order to further testify the reliability of the above results, we conducted an analysis of β-glucuronidase (GUS) dyeing. The analysis showed that AnEXPA1 was only induced by cold stress, whereas AnEXPA2 responded to hormone induction. AnEXPA1 and AnEXPA2 transgenic Arabidopsis plants showed better tolerance to cold and drought stresses. Moreover, the ability to scavenge reactive oxygen species (ROS) was significantly improved in the transgenic plants, and expansin activity was enhanced. These results suggested that AnEXPA1 and AnEXPA2 play an important role in the response to abiotic stress. Our research contributes to a better understanding of the regulatory network of expansins and may benefit agricultural production.

Zygophyllum kansuense Y. X. Liou is a localized species and endemic to China. In this study, the complete chloroplast genome of Z. kansuense was sequenced and described. The length of complete chloroplast genome was 105,383 base pairs (bp) for Z. kansuense, the genome with 33.8% GC content, containing a large single-copy (LSC) of 79,594 bp, a small single-copy (SSC) of 17,061 bp, and a pair of inverted repeats (IRs) of 4,364 bp. The genome contains 112 genes, including 75 protein-coding genes, 33 tRNA genes, and four rRNA genes. The phylogenetic analysis indicated that Z. kansuense and others of Zygophyllum clustered into one clade with a high support value.