Plant Growth-Promoting Rhizobacteria Improve Growth, Morph-Physiological Responses, Water Productivity, and Yield of Rice Plants Under Full and Deficit Drip Irrigation

Abstract

Inoculating rice plants by plant growth promoting rhizobacteria (PGPR) may be used as a practical and eco-friendly approach to sustain the growth and yield of drought stressed rice plants. The effect of rice inoculation using plant growth hormones was investigated under drip full irrigation (FI; 100% of evapotranspiration (ETc), and deficit irrigation (DI; 80% of ETc) on growth, physiological responses, yields and water productivities under saline soil (ECe = 6.87 dS m−1) for 2017 and 2018 seasons. Growth (i.e. shoot length and shoot dry weight), leaf photosynthetic pigments (chlorophyll ‘a’ and chlorophyll ‘b’ content), air–canopy temperature (Tc–Ta), membrane stability index (MSI%), and relative water content, (RWC%) chlorophyll fluorescence (Fv/Fm) stomatal conductance (gs), total phenols, peroxidase (PO), polyphenol oxidase (PPO), nitrogen contents and water productivities (grain water productivity; G-WP and straw water productivity; S-WP) were positively affected and significantly (p < 0.05) differed in two seasons in response to the applied PGPR treatments. The highest yields (3.35 and 6.7 t ha−1 for grain and straw yields) as the average for both years were recorded under full irrigation and plants inoculated by PGPR. The results indicated that under water scarcity, application of (I80 + PGPR) treatment was found to be favorable to save 20% of the applied irrigation water, to produce not only the same yields, approximately, but also to save more water as compared to I100%.

Drought-Tolerant Landrace Rice Norungan Harbors Novel Putative Competitive Endophytes

“…Lysinibacillus fusiformis NE12 and Enterobacter cloaceae NE24 were identified as potential tryptophan-dependent IAA producers in the present work. The similar IAA-producing rice endophytes reported earlier were Serratia marcescens (Ji et al,2014), Ensifer garamanticus (Cardinale et al,2015), Microbacterium laevaniformis (Borah et al,2021), Bacillus megaterium (Abd El-Mageed et al,2022), Flavobacterium sp. (Walitang et al,2017), Herbaspirillum seropedicae, Azorhizobium caulinodans, Rhizobium daejeonense (Liu et al,2022).…”

“…Borah et al (2021) screened 70 rice endophytes and found Bacillus tequilensis, Microbacterium tesaceum, and M. enclense as potential nitrogen-fixing and mineral solubilizing (P and K) endophytes. Abd El-Mageed et al (2022) found that out of 49 rice endophytes, 16 strains were potential nitrogen-fixers and 36 strains mineral solubilizers. Only a few shared the multiple nutrient-providing traits and authenticated B. megaterium and B. subtilis as potential nutrient-transforming (N, P and K) rice endophytes.…”

Plant Growth-Promoting Rhizobacteria Improve Growth and Fruit Quality of Cucumber under Greenhouse Conditions

“…In similar studies [26], using Bacillus velezensis as inoculant of C. sativus, it was observed that the host plant modifies the root structure, which improves water and nutrient uptake, promoting a higher photosynthetic rate. It has been suggested that the modification of the root structure of a cucumber plant is related to the phytohormone indoleacetic acid (IAA) produced by S. meliloti, A. radioresistens, and P. paralactis [11,14,27]. In addition, it has been reported that S. meliloti and A. radioresistens possess the ability to fix nitrogen and solubilize phosphate, resulting in an increase on the number of late-stage roots and root hairs, since these elements are essential for the plant to increase photosynthetic pigments and proteins, which improves photosynthetic activity and rate, having a positive effect on plant development and a greater accumulation of biomass [28,29].Furthermore, it has been pointed out that IAA is associated with cell division and differentiation, which improves the structure of the root system [30][31][32].…”

“…Currently, beneficial microorganisms have been applied in the plants as a sustainable alternative for food production [11], likewise, the combination with synthetic fertilizers has led to increased plant growth and productivity [7,12]. Plant growth-promoting rhizobacteria (PGPR) are a microorganism group able to increase the shoot and root length, improve water and nutrient absorption, and improve fruit quality and productivity in plants [13].…”

The Integration Efficacy between Beneficial Bacteria and Compost Tea on Soil Biological Activities, Growth and Yield of Rice Under Drought Stress Conditions

“…Recently several experimental solutions have been applied to treat the effects of water stress in rice. One effective solution was the use of plant growth promoting rhizobacteria (Abd El-Mageed et al 2022), and foliar spray with organic nutrients i.e. compost tea (Moridi et al 2019).…”