Diverse nodule bacteria were associated with Astragalus species in arid region of northwestern China

Abstract

The legume species of Astragalus as traditional Chinese medicine source and environmental protection plants showed an extensive distribution in the arid region of northwestern China. However, few rhizobia associating with Astragalus have been investigated in this region so far. In this study, 78 endophytic bacteria were isolated from root nodules of 12 Astragalus species and characterized by the PCR-RFLP of 16S rRNA gene and symbiotic genes together with the phylogenetic analysis. Results showed that the majority (53%) of isolates are non-nodulating Agrobacterium sp. and the rest are Mesorhizobium genomic species (41%), Ensifer spp. and Rhizobium gallicum (6%), respectively. Mesorhizobium genomic species are broadly distributed in the Astragalus symbioses and most of them share similar symbiotic genes. It seems that horizontal gene transfer occurred frequently among different genomic species independent of their original hosts and sites. Astragalus adsurgens is nodulated by a widely range of rhizobial species in the nodulation test, revealing that it could play an important role in diversification of Astragalus symbionts and that might be a reason for its wide adaptation to diverse environments.

WITHDRAWN: Phenotypic Diversity of Wild Astragalus polycladus Resources

“…Astragalus polycladusis a cold and drought-resistant plant with a well-developed root system, which can be used for soil and water conservation and other aspects of ecological grasses. There are a large number of rhizobacteria in its root system, which not only provide a nitrogen source for the Astragalus polycladus, but also can make the inorganic nitrogen into organic nitrogen to be preserved in the soil, to play the role of improving the soil, and provide su cient nitrogen for the neighboring grasses, and there have been relevant studies to prove that the Astragalus polycladus and grass pasture mixing can improve the yield of pasture grasses (Osaloo et al 2003;Dong et al 2023;Chen et al 2015). In addition, the medicinal value of Astragalus polycladus very high, according to "Tibetan Materia Medica" and the database of Tibetan medicinal resources of the Key Laboratory of Tibetan Medicine Research of the Chinese Academy of Sciences, Astragalus polycladus used for treating febrile illnesses, oedema, boredom, sores and fever, and externally used for anti-in ammation, etc.…”

Effects of Hedysarum leguminous plants on soil bacterial communities in the Mu Us Desert, northwest China

“…This study showed that in addition to dominant nitrogen-fixing rhizobia, there were also other, nonsymbiotic endophytes in the roots of Hedysarum (Msaddak et al, 2018). It has also been reported that endophytic bacteria, which are known to exist in plant tissues, can facilitate plant growth (Rajendran, Sing, Desai, & Archana, 2008;Rivas et al, 2002) and that other root endophytes co-inoculated with rhizobia can accelerate the growth and nodulation of leguminous plants (Chen et al, 2015;Xu, Zhang, Wang, Chen, & Wei, 2014).…”

“…In addition, Phyllobacterium has also been detected in the roots of Lupinus micranthus in Tunisia, indicating that this bacterial genus can boost the rapid nodulation of this Tunisian xeric leguminous plant (Msaddak et al., 2018). It has also been reported that endophytic bacteria, which are known to exist in plant tissues, can facilitate plant growth (Rajendran, Sing, Desai, & Archana, 2008; Rivas et al., 2002) and that other root endophytes co‐inoculated with rhizobia can accelerate the growth and nodulation of leguminous plants (Chen et al., 2015; Xu, Zhang, Wang, Chen, & Wei, 2014). Together, these results demonstrate that nonsymbiotic endophytes in roots may coordinate with nitrogen‐fixing rhizobia and exert various functions.…”

Species identity and combinations differ in their overall benefits to Astragalus adsurgens plants inoculated with single or multiple endophytic fungi under drought conditions

“…(Leguminosae) is a native perennial herbaceous mainly distributed in the desert region of Northwest China (Liu et al, 2018 ). As typical desert herbage and fine forage, this species is a preferred plant for desert ecological restoration and desert grassland planting because it is strong drought and sandstorm resisting plant (Chen et al, 2013 ). Therefore, considering the concept of sustainability and the need to enhance the growth status and drought resistance of grassland plants, understanding the interaction between plants and beneficial microbes is crucial to receive benefit from the symbiotic mechanisms.…”