Survey of Plant Drought-Resistance Promoting Bacteria from Populus euphratica Tree Living in Arid Area

Abstract

Two hundred and thirty-two bacterial strains were isolated from the rhizospheric soil of Populus euphratica which is the dominant tree living in extreme arid regions in northwest China. Some strains with plant growth-promoting bacteria related metabolic characteristics were able to promote drought resistance in plants after inoculation. Ten strains with the greatest effects increased the dry weight of wheat shoots from 0.5 to 34.4 %, and the surface area of the root systems from 12.56 to 212.17 % compared to the control after drought treatment whereas no obvious promoting effect was observed in normal water conditions. These 10 strains were identified to be of the genera Pseudomonas, Bacillus, Stenotrophomonas and Serratia by 16S rRNA (rrs) gene sequence alignment. Among these strains, Serratia sp. 1-9 and Pseudomonas sp. 5-23 were the two most effective strains. Both of them produced auxin and the production increased significantly when cultured under simulated drought conditions which are inferred to be the most plausible mechanism for their plant growth-promoting effect under drought stress.

Drought Stress and Root-Associated Bacterial Communities

“…Screening of putative plant growth-promoting bacteria (PGPB) in vivo on droughted plants is a frequent strategy used to confirm growth promotion, and has been done in a variety of plant species ( Mayak et al, 2004 ; Marasco et al, 2012 ; Yandigeri et al, 2012 ; Timmusk et al, 2014 ; Wang et al, 2014 ; Cherif et al, 2015 ). PGPB may enhance drought tolerance in plants other than those they were originally isolated from ( Marasco et al, 2013 ; Wang et al, 2014 ), and in some cases enhance plant growth only under drought conditions ( Wang et al, 2014 ; Rolli et al, 2015 ). Creating consortia of bacteria may have greater and synergistic effects at alleviating drought than applications of individual genera ( Knoth et al, 2014 ; Timm et al, 2016 ).…”

Plant Growth Promoting Bacteria Associated with Langsdorffia hypogaea-Rhizosphere-Host Biological Interface: A Neglected Model of Bacterial Prospection

“…Our isolates H59, H66, and H70 showed similarity to this genus and were able to produce siderophores and IAA and to fix N 2 , besides inhibiting enteropathogens. Another recent work isolated bacteria from the rhizospheric soil of Populus euphratica and identified ten strains that induced a significant increase in dry weight of buds and roots of wheat ( Wang et al, 2014 ). These isolates were identified as being from the genera Pseudomonas , Bacillus , Stenotrophomonas , and Serratia .…”

“…23/05 were the most effective strains. Both produced auxin, and significantly increased production when grown under simulated dry conditions, leading to a direct effect on promoting plant growth under drought stress ( Wang et al, 2014 ). Similarly, a work identified 12 endophytic bacteria characterized as diazotrophic, two species belonging to the genus Paenibacillus , three to the genus Mycobacterium , three to the genus Bacillus , and four to the genus Klebsiella ( Ji et al, 2014 ).…”

Culturable diazotrophic bacterial community associated with Agave sisalana P. plants from semi-arid regions in Brazil

“…Therefore, the biochemical and physiological characteristics of Bacillus (e.g. endospore forming bacteria) can promote its survival in environments under stress conditions (Wang et al, 2014). It is important to verify the systemic distribution of Bacillus in sisal since endophytic Bacillus species can influence plant growth promotion, tolerance to water deficiency, and crop protection against diseases (Ribeiro et al, 2018;Vigani et al, 2018).…”