Alleviation of Salt Stress in Upland Rice (Oryza sativa L. ssp. indica cv. Leum Pua) Using Arbuscular Mycorrhizal Fungi Inoculation

Abstract

Arbuscular mycorrhizal fungi (AMF) symbionts not only promote the growth of host plant but also alleviate abiotic stresses. This study aimed to investigate the putative role of AMF in salt stress regulation of upland pigmented rice cv. Leum Pua (LP) comparing with Pokkali salt tolerant (positive check). In general, LP is a variety of glutinous rice that contains anthocyanin pigment in the black pericarp, due to which it possesses high antioxidant activities compared to non-pigmented rice. Pot experiment was conducted to evaluate the impact of inoculated AMF, Glomus etunicatum (GE), Glomus geosporum (GG), and Glomus mosseae (GM) strains, in the LP plantlets subjected to 0 (control) or 150 mM NaCl (salt stress) for 2 weeks in comparison with Pokkali (a salt tolerant rice cultivar), which was maintained as a positive check. Root colonization percentage under NaCl conditions ranged from 23 to 30%. Na + content in the flag leaf tissues was increased to 18-35 mg g −1 DW after exposure to 150 mM NaCl for 14 days in both inoculated and un-inoculated LP plants, whereas Na:K ratio was very low in cv. Pokkali. Interestingly, sucrose content in the flag leaf tissues of un-inoculated LP plants under salt stress was increased significantly by 50 folds over the control as an indicator of salt stress response, whereas it was unchanged in all AMF treatments. Fructose and free proline in GE inoculated plants under salt stress were accumulated over control by 5.75 and 13.59 folds, respectively, for osmotic adjustment of the cell, thereby maintaining the structure and functions of chlorophyll pigments, F v /F m , PSII , and stomatal function. Shoot height, flag leaf length, number of panicles, panicle length, panicle weight, and 100-grain weight in GE inoculated plants of cv. LP under salt stress were maintained similar to cv. Pokkali. Interestingly, cyanidin-3-glucoside (C3G) and peonidin-3-glucoside (P3G) in the pericarp of cv. LP were regulated by GE inoculation under salt stress conditions. In summary, AMF-inoculation in rice crop is a successful alternative approach to reduce salt toxicity, maintain the yield attributes, and regulate anthocyanins enrichment in the pericarp of grains.

Arbuscular mycorrhizal fungi (AMF) species and abundance exhibit different effects on saline-alkaline tolerance in Leymus chinensis

“…AMF are ubiquitous soil microorganisms that form mutual symbiotic association with over 80% terrestrial plants (Smith and Read 2008). Several studies have indicated that AMF have the ability to enhance plant tolerance to saline-alkaline stress through promoting plant growth, improving gas exchange, enhancing nutrient uptake and maintaining ion balance (Evelin et al 2009;Tisarum et al 2020). Mycorrhizal plants had higher net photosynthetic rate, stomatal conductance and chlorophyll content compared to non-mycorrhizal plants under saline-alkaline stress (Lin et al 2017;Kong et al 2020).…”

“…Although many studies have indicated the beneficial effects of AMF on salt stress alleviation in various plants (Shi-chu et al 2019;Tisarum et al 2020;Kong et al 2020), but the magnitudes of effect greatly differ among these studies. Simultaneously, the different impacts of AMF inoculation on the alleviation of salt stress have been also found in citrus seedlings with differential salinity tolerance (Navarro et al 2014).…”

Improved salt tolerance of Chenopodium quinoa Willd. contributed by Pseudomonas sp. strain M30-35

“…Phosphorus content was determined by the molybdenum blue spectrophotometry method ( Tisarum et al, 2020 ). Dried shoot and root samples (100 mg) were added to 8 mL of H 2 SO 4 and soaked overnight.…”

Bayesian Network Analysis of Lysine Biosynthesis Pathway in Rice

“…Nearly 5% (77 million hectares) of the global arable land has excess salinity [46]. Due to various factors such as climate change and irrigation malpractices, the soil salinity is predicted to increase by 16.2 million hectares by 2050 [47,48]. Among abiotic stresses, soil salinity is the second largest cause of crop loss in rice after drought [49,50].…”