White rot disease protection and growth promotion of garlic (Allium sativum) by endophytic bacteria

Abstract

Thirty‐five bacterial isolates, recovered from the healthy bulbs of Allium sativum that grow in different sites of China, were screened for their ability to produce hydrolytic enzymes and metabolites and to dissolve inorganic phosphorus in vitro. These 35 endophytes inhibited the growth of the causal agent of white rot disease, Sclerotium cepivorum (Sc), by 19–64%. The isolates 153 (Bacillus siamensis) (Bs) and 136 (Streptomyces setonii) (Ss) were found to be the most effective in decreasing Sc disease incidence, both by 66%. In addition, there was a significant enhancement in the growth of garlic plants pretreated with isolates 153 Bs and 136 Ss. Isolate 136 could not produce indole‐3‐acetic acid (IAA) and did not exhibit an inorganic phosphorus solubilization ability in vitro. Thus, growth promotion by this Streptomyces sp. is likely to be mediated by a different, and perhaps novel, mechanism to that typically associated with growth promoting bacteria. An increase in expression of alliin lyase 2 was found in garlic plants treated with 153 Bs. By extension, the quantity of the antimicrobial sulphoxide, alliin, was also increased in 153 Bs‐treated and Sc‐inoculated plants, relative to the Sc‐inoculated controls. These results indicated that this bacterial endophyte might protect A. sativum not only by direct antibiosis, but also by enhancing the expression of alliin lyase 2 and the concomitant production of alliin.

Response of garlic varieties growth towards the use of biological fertilizer

“…As they act as the PGPR (Plant Growth Promoting Rhizobacteria) microbes in the soil, they can produce the plant hormone auxin, gibberellin and cytokinin, which helps to stimulate an increase in plant height [7]. In addition, both microbes are able to inhibit the growth of the causative agent of the white rot disease [8]. The discussion should be more directed at the effect of Trichoderma sp.…”

Biocontrol potential and growth-promoting effect of endophytic fungus Talaromyces muroii SD1-4 against potato leaf spot disease caused by Alternaria alternata

“…When colonized throughout plant tissues, endophytic microorganisms can provide systemic tolerance to many plant pathogens and as endophytes interact closely with the host plant, they show great potential to promote plant growth through phytohormone regulation, phosphate solubilization and iron carrier production [ 19 – 21 ]. The endophyte Streptomyces sitangensis 136 was found to not only inhibit the growth of Sclerotium cepivorum and reduce the incidence of white rot disease, but also significantly promoted the growth of garlic plants [ 22 ]. The fungal endophytes of Trichoderma asperellum , Epicoccum nigrum and A. longipes showed broad-spectrum antifungal activity against Fusarium thapsinum , E. sorghinum , A. alternata and Curvularia lunata and plant growth-promoting traits under in vitro and in vivo field conditions as well as effective colonization [ 23 ].…”

Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in Taiwan

“…Allium species are an abundant source of endophytic microorganisms including bacteria and fungi with many beneficial properties to plants, such as growth promotion and pathogen control [ 26 , 27 ]. For instance, Murtado et al isolated 40 endophytic bacteria from onions ( A. cepa ) and among them, bacterial strain BBP5.2 exhibited promising inhibition of Colletotrichum sp., one of the major foliar pathogens of onions in Brebes, Central Java [ 28 ].…”