Inoculation treatments affect the migration and colonisation of rhizobia in alfalfa (Medicago sativa L.) plants. (3rd April 2018)

• Record Type: Journal Article
• Authors: Miao, Yang-yang; Shi, Shang-li; Nie, Zhong-nan; Kang, Wen-juan; Frazier, Taylor P
• Is Part Of: Acta agriculturæ Scandinavica. Volume 68:Number 3(2018)
• Page Start: 199
• Page End: 212
• Publication Date: 2018-04-03
• Subjects: Alfalfa -- colonisation dynamics -- fluorescent tagged rhizobia -- inoculation treatments -- reproductive stage; Horticulture -- Periodicals; Soil science -- Periodicals; Crops and soils -- Periodicals; Plant-soil relationships -- Periodicals; 630
• DOI: 10.1080/09064710.2017.1378710
• Languages: English
• ISSNs: 0906-4710

Abstract

ABSTRACT: Purpose: The purposes of this study were to characterise the migration and the colonisation dynamics of two different fluorescent-tagged rhizobia in various alfalfa tissues (especially in seeds); and also to develop efficient inoculation treatments to promote colonisation ability of target rhizobia in elite seed varieties. Materials and methods: Four treatments (root drench, root damaging and drench, root drench with matrine, and flower spray) were applied to inoculate alfalfa with two fluorescent-tagged rhizobia, Ensifer meliloti LZgn5f (gn5f) and Ensifer meliloti 12531f (12531f), at three different growth stages; bud, flower and pod stages. The migration and colonisation dynamics of the two fluorescent tagged rhizobia strains were monitored using UV lamp detection and a stereo fluorescence microscopy. Results: The results showed that both rhizobia strains mainly colonised the roots and could migrate to aerial tissues. In aerial tissues, when alfalfa plants were inoculated during the bud stage, both rhizobia strains mainly colonised the leaves and stems; during the flower stage, a spray inoculation treatment resulted in more 12531f colonising reproductive tissues, while during the pod stage, more rhizobial strains gn5f colonised seeds using the root drench with matrine treatment. Conclusions: These results indicate that endophytic rhizobia are natural inhabitants of internal regions of roots, stems, leaves and that the endophytes may arise from reproductive tissues, such as seeds. Understanding the population dynamics of endophytic rhizobia in alfalfa would considerably improve the survival of target rhizobia during seed transfer. Combining target endogenous rhizobial species with good alfalfa seed varieties may lead to the development of a novel breeding method.