[Zhao, Yunlin; Xu, Zhenggang; Peng, Jiao] Cent South Univ Forestry & Technol, Coll Life Sci & Technol, 498 Shaoshan South Rd, Changsha 410004, Hunan, Peoples R China.;[Xu, Zhenggang; Dong, Meng] Hunan City Univ, Coll Chem & Environm Engn, 518 Yingbin Rd, Yiyang 413000, Hunan, Peoples R China.;[Ge, Yu] Hubei Univ Nationalities, Coll Forestry, 39 Xueyuan Rd, Enshi 445000, Hubei, Peoples R China.;[Yang, Guiyan] Northwest A&F Univ, Coll Forestry, Lab Walnut Res Ctr, Yangling 712100, Shaanxi, Peoples R China.
[Yang, Guiyan] Northwest A&F Univ, Coll Forestry, Lab Walnut Res Ctr, Yangling 712100, Shaanxi, Peoples R China.
Osmotic tolerance;V-ATPase G subunit;Juglans regia;ROS scavenger
JrVHAG1 is an important candidate gene for plant osmotic tolerance regulation. Vacuolar H+-ATPase (V-ATPase) is important for plant responses to abiotic stress; the G subunit is a vital part of V-ATPase. In this study, a G subunit of V-ATPase was cloned from Juglans regia (JrVHAG1) and functionally characterized. JrVHAG1 transcription was induced by mannitol that increasing 17.88-fold in the root at 12 h and 19.16-fold in the leaf at 96 h compared to that under control conditions. JrVHAG1 was overexpressed in Arabidopsis and three lines (G2, G6, and G9) with highest expression levels were selected for analysis. The results showed that under normal conditions, the transgenic and wild-type (WT) plants displayed similar germination, biomass accumulation, reactive oxygen species (ROS) level, and physiological index. However, when treated with mannitol, the fresh weight, root length, water-holding ability, and V-ATPase, superoxide dismutase, and peroxidase activity of G2, G6, and G9 were significantly higher than those of WT. In contrast, the ROS and cell damage levels of the transgenic seedlings were lower than those of WT. Furthermore, the transcription levels of V-ATPase subunits, ABF, DREB, and NAC transcription factors (TFs), all of which are factors of ABA signaling pathway, were much higher in JrVHAG1 transgenic plants than those in WT. The positive induction of JrVHAG1 gene under abscisic acid (ABA) treatments in root and leaf tissues indicates that overexpression of JrVHAG1 improves plant tolerance to osmotic stress relating to the ABA signaling pathway, which is transcriptionally activated by ABF, DREB, and NAC TFs, and correlated to ROS scavenging and V-ATPase activity.
The complete chloroplast genome sequence of Lupinus westianus, an endangered and endemic species to Florida, United States, has been assembled from Illumina pair-end sequencing. The chloroplast genome structure of L. westianus is a circular molecule of 154,270 bp in length, with a large single copy (LSC) region of 82,437 bp, a small single copy (SSC) region of 15,853 bp, and a pair of inverted repeats (IRs) regions of 27,990 bp. The total G+C content of chloroplast genome is 36.47%, and while it is 41.56% of IRs, which was higher than LSC and SSC regions. The genome contained 130 genes, including 85 protein coding genes, 37 tRNA genes and 8 rRNA genes, of which 18 were duplicated in the IRs region. The phylogenetic analysis indicated that L. westianus was clustered together with other two genus of Lupinus, L. luteus and L. albus. The chloroplast genome of L. westianus laid a good foundation for genetic resoures conservation. The chloroplast genome reported provided useful genomic resources not only for the exchange of information between different species, but also for the population genetics of L. westianus and its phylogenetic and evolutionary studies.