Search Results (2)

The Qinghai–Tibetan Plateau (QTP) is under serious desertification stress, which has been receiving increasing attention. Although the restoration of surface vegetation is crucial, the growth of plants is often hindered by unfavorable nutrient-deficient conditions. The plant-associated endophytic microbiome is considered the secondary genome of the host and plays a significant role in host survival under environmental stresses. However, the community compositions and functions of plant-endophytic microorganisms in the QTP desertification environments remain unclear. Therefore, this study investigated the endophytic microbiome of the pioneer plant Gueldenstaedtia verna on the QTP and its contribution to host growth under stressful conditions. The results showed that nutrient-deficient stresses strongly influenced the microbial community structures in the rhizosphere. The impacts of these stresses, however, decreased from the rhizosphere community to the plant endophytes, resulting in consistent plant endophytic microbial communities across different sites. Members of Halomonas were recognized as keystone taxa in the endophytic microbiome of G. verna. Correlation analysis, metagenome-assembled genomes (MAGs), and comparative genome analyses have shown that the keystone taxa of the plant endophytic microbiome may promote plant growth through pathways such as nitrogen fixation, IAA, and antioxidant production, which are important for improving plant nutrient acquisition and tolerance. This finding may provide a crucial theoretical foundation for future phytoremediation efforts in desertification environments on the Qinghai-Tibet Plateau. Full article

The genus Gueldenstaedtia belongs to Papilionaceae’s inverted repeat-lacking clade (IRLC) and includes four species distributed throughout Asia. We sequenced the chloroplast genome of G. verna and compared it with those of the IRLC clade. The genome was 122,569 bp long, containing 77 protein-coding genes, 30 tRNAs, and 4 rRNAs. Comparative analyses showed that G. verna lost one inverted repeat region, the rps16 gene, an intron of rpoC1, and two introns of clpP. Additionally, G. verna had four inversions (~50 kb inversion, trnK–psbK; ~28 kb inversion, accD–rpl23; ~10 kb inversion, rps15–trnL; ~6 kb inversion, trnL–trnI) and one reposition (ycf1). Its G + C content was higher than that of other IRLC species. The total length and number of repeats of G. verna were not significantly different from those of the other IRLC species. Phylogenetic analyses showed that G. verna was closely related to Tibetia. A comparison of substitution rates showed that ycf2 and rps7 were higher than one, suggesting that these were positive selection genes, while others were related to purified selection. This study reports the structure of the chloroplast genome of a different type, i.e., with four inversions and one reposition, and would be helpful for future research on the evolution of the genome structure of the IRLC. Full article