Induction of systemic resistance in Chinese cabbage against black rot by plant growth-promoting rhizobacteria

Abstract

Black rot, caused by Xanthomonas campestris pv. campestris, is the most important and potentially destructive disease of cabbage. The objectives of this study were to select plant growth-promoting rhizobacteria (PGPR) strains and to form strain mixtures with the capacity to elicit induced systemic resistance or to increase plant growth in Chinese cabbage. In preliminary screening, 10 of 12 tested individual PGPR strains (AP136, AP188, AP209, AP213, AP217, AP218, AP219, AP282, AP295, and AP305) reduced the number of foliar lesions, and 2 PGPR strains (AP7 and AP18) increased all tested parameters of plant growth promotion, including shoot fresh weight, shoot dry weight, root fresh weight, root dry weight and plant diameter. In advanced tests, four individual stains (AP136, AP209, AP282 and AP305) were combined into mixture-1. Mixture-2 contained all strains in mixture one plus three additional stains (AP7, AP18 and AP218). Both mixtures and three individual strains (AP136, AP209 and AP305) significantly reduced the number of black rot lesions, and mixture-2 increased shoot dry weight and root dry weight in greenhouse tests. In a field test, all the tested treatments significantly reduced disease incidence on whole plants at three weeks after transplanting and reduced head disease severity at harvest time. All treatments also increased marketable yield compared to the nonbacterized control. These results demonstrated that specific individual PGPR strains and strain mixtures induced systemic resistance to black rot in the greenhouse and field.

Biological control of Heterodera glycines by spore-forming plant growth-promoting rhizobacteria (PGPR) on soybean

“…velezensis ) increased shoot and root dry weights in the greenhouse test. They found that those individual strains and mixtures increased marketable yield of Chinese cabbage in the field [31]. Our study is in an agreement with previous research that individual or mixtures of PGPR strains can promote plant growth under greenhouse or field conditions and that some PGPR strains can reduce plant-parasitic nematode population density.…”

Changes in soil bacterial community structure as a result of incorporation of Brassica plants compared with continuous planting eggplant and chemical disinfection in greenhouses

“…Several beneficial bacterial strains isolated from the rhizosphere of Brassica species [16] are associated with plant growth and promoting rhizobacteria (PGPR), such as Agrobacterium , Azospirillum , Bacillus , Enterobacter , Pseudomonas and Rhizobium [17]. These microorganisms can promote plant growth by regulating nutritional and hormonal balances, producing plant growth regulators [18], solubilizing nutrients and inducing resistance against plant pathogens [19]. Some studies have shown that the incorporation of Brassica crops into soil inhibited the growth of a variety of soil-borne pathogens of potato, including Rhizoctonia solani , Phytophthora erythroseptica , Pythium ultimum , Sclerotinia sclerotiorum and Fusarium sambucinum , and reduced subsequent potato seedling disease by 40–83% [20].…”

Isolation and characterization of plant growth promoting bacteria (PGPB) from anaerobic digestate and their effect on common wheat (Triticum aestivum) seedling growth

“…In this study, Bacillus isolates (MAD-05, Bacillus subtilis and TAD-05, Bacillus licheniformis) showed high antifungal activity of 62.75% and 43.53% PGI, which may contribute to the competition for space and nutrients and secretion of antifungal compounds (Yang et al, 2015). Similarly, Bacillus species have been widely reported to have antifungal activity against a wide variety of phytopathogens (Ji et al, 2014;Kumar et al, 2012;Liu et al, 2016). Therefore, further application of Bacillus isolates as biocontrol agents could be expected.…”