Abstract
Desmodium spp. are leguminous plants belonging to the tribe Desmodieae of the subfamily Papilionoideae. They are widely distributed in temperated and subtropical regions and are used as forage plants, for biological control, and in traditional folk medicine. The genus includes pioneer species that resist the xerothermic environment and grow in arid, barren sites. Desmodium species that form nitrogen-fixing symbiosis with rhizobia play an important role in sustainable agriculture. In Argentina, 23 native species of this genus have been found, including Desmodium incanum. In this study, a total of 64 D. incanum-nodulating rhizobia were obtained from root nodules of four Argentinean plant populations. Rhizobia showed different abiotic-stress tolerances and a remarkable genetic diversity using PCR fingerprinting, with more than 30 different amplification profiles. None of the isolates were found at more than one site, thus indicating a high level of rhizobial diversity associated with D. incanum in Argentinean soils. In selected isolates, 16S rDNA sequencing and whole-cell extract MALDI TOF analysis revealed the presence of isolates related to Bradyrhizobium elkanii, Bradyrhizobium japonicum, Bradyrhizobium yuanmingense, Bradyrhizobium liaoningense, Bradyrhizobium denitrificans and Rhizobium tropici species. In addition, the nodC gene studied in the selected isolates showed different allelic variants.Isolates were phenotypically characterized by assaying their growth under different abiotic stresses. Some of the local isolates were remarkably tolerant to high temperatures, extreme pH and salinity, which are all stressors commonly found in Argentinean soils. One of the isolates showed high tolerance to temperature and extreme pH, and produced higher aerial plant dry weights compared to other inoculated treatments. These results indicated that local isolates could be efficiently used for D. incanum inoculation.
Highlights
The genus Desmodium is a large member of the Papilionaceae (Fabaceae) family [21]
In order to study the diversity of native rhizobial populations able to nodulate D. incanum, different regions from Argentina were sampled and investigated for the presence of nodulated plants naturally present at the different sampling sites (Table S1)
A rhizobial collection was assembled comprising a total of 64 isolates, including those recovered from different trap plants grown in pots (62 isolates), as well as isolates from field-nodulated plants
Summary
The genus Desmodium is a large member of the Papilionaceae (Fabaceae) family [21]. It contains about 350 species which are mainly distributed in tropical and subtropical regions of the world, as well as approximately 23 species that are distributed in Argentina [49]. Within the Leguminosae, the tribe Desmodieae (Benth.) Hutch is known for its significant contribution to forage production in the tropics, and includes several species of agronomic concern. Native leguminous plants are frequently found in these areas where legume–rhizobial symbiosis is responsible for an increase in the nitrogen (N) content of the soil-plant system via the mechanism of biological nitrogen fixation [46]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
