A Mixture of Piper Leaves Extracts and Rhizobacteria for Sustainable Plant Growth Promotion and Bio-Control of Blast Pathogen of Organic Bali Rice

Abstract

Rice is a crop that is consumed as a staple food by the majority of the people in the world and therefore failure in rice crops, due to any reason, poses a severe threat of starvation. Rice blast, caused by a fungus Pyricularia oryzae, has been ranked among the most threatening plant diseases of rice and it is found wherever rice is grown. All of the rice blast disease management strategies employed so far have had limited success and rice blast has never been eliminated from rice fields. Hence, there is a need to look for the best remedy in terms of effectiveness, sustainability, and organic nature of the method. This study was aimed at determining the plant growth-promoting and fungicidal effects of a mixture of Piper caninum and Piper betle var. Nigra leaves extracts and rhizobacteria. Gas chromatography–mass spectrophotometry (GC-MS) analysis of a mixture of leaves extracts of these plants revealed the presence of new bioactive compounds such as alpha.-gurjunene, gamma.-terpinene, and ethyl 5-formyl 3-(2-ethoxycarbonyl) in a mixture of leaves extracts of P. caninum and P. betle var. Nigra. The mixture of these extracts reduced the intensity of blast disease, inhibited P. oryzae, and improved the growth, yield, and quality of Bali rice. All treatments comprising of different concentrations of a mixture of leaves extracts of P. caninum and P. betle var. Nigra plus rhizobacteria exhibited biocontrol and bioefficacy. However, a 2% concentration of a mixture of these leaves extracts with plant growth-promoting rhizobacteria (PGPR) exhibited potent inhibition of growth of P. oryzae, a significant reduction in the intensity of blast disease, and a maximum increase in growth, yield, and quality of Bali rice. In the 15th week, the intensity of blast disease decreased from 80.18% to 7.90%. The mixture of leaves extract + PGPR also improved the height of the plant, the number of tillers, number of leaves, number of grains per panicle, number of heads per panicle, and the full-grain weight per clump. Applications of various concentrations of a mixture of leaves extracts + PGPR resulted in improvement in the potential yield of rice, however, the application of 2% extracts + PGPR gave the highest potential yield of 5.61 tha−1 compared to the low yields in the control and other treatments. The high grain yield observed with the treatment was caused by the low intensity of blast disease. This treatment also strengthened the stem and prevented the drooping of the plant and improved the quality of rice grain.

Production, Purification, and Characterization of Bacillibactin Siderophore of Bacillus subtilis and Its Application for Improvement in Plant Growth and Oil Content in Sesame

“…Considering their ability in crop improvement, they are used as a substitute for chemical application in agriculture. Most of the rhizosphere bacteria secrete secondary metabolites called siderophores which act as chelating agents for ferric iron, produced under low iron stress [51][52][53][54][55].…”

Production of Plant Beneficial and Antioxidants Metabolites by Klebsiellavariicola under Salinity Stress

“…Halophilic Klebsiella sp. isolated from the plant roots showed tolerance to higher levels (4 to 8% NaCl) of salts [ 22 ]. Singh et al, reported the growth of Klebsiella sp.…”

“…Various reports claim that the application of PGPR for sustainable improvements in nutrients and the health of soil and plants [ 4 , 9 , 10 , 11 ]. PGPR are known to produce a wide variety of plant growth-promoting traits that include siderophores [ 10 , 11 ], phytohormones [ 12 , 13 ], hydrolytic enzymes [ 14 ], exopolysaccharide [ 15 , 16 , 17 ], stress-tolerant metabolites [ 18 , 19 , 20 , 21 ], and phosphate solubilization [ 22 , 23 ], etc. PGPR through these metabolites promotes seed germination, root and shoot growth, the level of soil and plant nutrients [ 13 , 21 , 24 ].…”

Biosurfactant producing multifarious Streptomyces puniceus RHPR9 of Coscinium fenestratum rhizosphere promotes plant growth in chilli

“…This can be met with the help of plant growth-promoting microorganisms (PGPM) [ 7 ] that colonize the rhizosphere and exert beneficial effects on the host plant. PGPM produces phytohormones, hydrolytic enzymes, organic acids, siderophore and biosurfactants to enhance soil fertility, crop yield and combat phytopathogens [ 8 ]. Streptomyces spp.…”