Endophytic fungus Phomopsis liquidambari and different doses of N-fertilizer alter microbial community structure and function in rhizosphere of rice

Abstract

Microbial community structure and functions of rhizosphere soil of rice were investigated after applying low and high doses of nitrogenous fertilizer and Phomopsis liquidambari. Average well color development, substrate richness, catabolic diversity and soil enzymes activities varied after applying N-fertilizer and P. liquidambari and were greater in P. liquidambari treated soil than only N-fertilization. Multivariate analysis distinctly separated the catabolic and enzymes activity profile which statistically proved alteration of microbial functional diversity. Nitrogen fertilizer altered microbial community structure revealed by the increased content of total PLFAs, specific subgroup marker PLFAs except fungal PLFAs and by the decreased ratio of G + /G− , sat/monunsat, iso/anteiso, F/B except trans/cis while P. liquidambari inoculation enhanced N-fertilization effect except increased fungal PLFA and decreased trans/cis. PCA using identified marker PLFAs revealed definite discrimination among the treatments which further statistically confirmed structural changed of microbial community. Nitrogenase activity representative of N-fixing community decreased in N-fertilizer treatment while P. liquidambari inoculation increased. In short, application of P. liquidambari with low doses of N-fertilizer improved rice growth and reduced N-fertilizer requirement by increasing enzymes activities involved in C, N and P cycling, structural and functional diversity of microbes, nitrogenase activity involved in N 2 fixation and accumulation of total-N.Rice (Oryza sativa L.) is the second largest crop in terms of planted area and yield in the world. The cultivation of rice gives rise to anoxic conditions in growing season but aerobic conditions during non-growing season 1 . Thus, composition and structure of microbial community in rice field are diverse and very complicated 2 . Agricultural management practices, particularly inputs of fertilizers and manure, tillage, cover crops, cropping system and season, soil pH and application of plant growth promoting bacteria or fungi have large impacts on the size and activity of soil microbial communities [3][4][5][6][7][8] . Nitrogen is the top most important macronutrients and limiting factor for plant growth and development 9 . Soils are routinely fertilized to overcome N-limitation and maximize crop yield. But, repeated fertilizer applications change soil physical, chemical and biological properties consequently directly or indirectly influence the growth and activity of certain group of microbes and adaptation ability of different groups of microbes varies with nutritional status 10,11 . The rhizosphere of plant itself is also a unique ecological niche and shapes the structure of microbial community by releasing specific substrates or by the specific physical, chemical and biotic environment created by the plant root in terms of O 2 , pH etc. 12,13 . Quality and quantity of root exudates depends on plant species, nutrient levels, biotic and abiotic stresses and colonization by PGP mi...

Amelioration of drought effects in wheat and cucumber by the combined application of super absorbent polymer and potential biofertilizer

“…In addition, the activity of alkaline phosphatase in different treatments was higher than that of acid phosphatase, which might be related to the influence of alkaline soil. Similar results have been reported in rice inoculated with Phomopsis liquidambari under LN level (Siddikee et al, 2016).…”

“…No matter for wheat or cucumber, the BJ-18 + SAP group showed the strongest urease activity in all treatments, which might be related to the N-fixing ability of P. beijingensis BJ-18 (Wang et al, 2013). The activity of dehydrogenase, a vital indicator of microorganism activity, was increased after the application of inoculation to soil (Siddikee et al, 2016). Here, the highest activity of dehydrogenase and sucrose was detected in the BJ-18 + SAP group of wheat rhizosphere soil and L-56 + SAP group of cucumber rhizosphere soil, which was consistent with the survival of P. beijingensis BJ-18 and Bacillus sp.…”

De novo Transcriptome Assembly of Phomopsis liquidambari Provides Insights into Genes Associated with Different Lifestyles in Rice (Oryza sativa L.)

“…Hence, endophytes that produce enzymes to decompose lignin and cellulose could decompose host tissue and persist as saprophytes following host senescence. Our research shows that the endophyte Phomopsis liquidambari B3 can establish a symbiotic relationship with rice ( Oryza sativa L.), systematically colonizing roots and aerial parts (Yang et al, 2014b ), which promotes the growth of rice, increasing yield and significantly reducing application of nitrogen fertilizer (Yang et al, 2014a , 2015 ; Siddikee et al, 2016 ). In the saprophytic phase, the fungus can decompose rice straw, promote litter organic matter cycling and the release of nutrients, improve soil microbial environments (Chen et al, 2013a ) and secrete laccase, cellulase and polyphenol oxidase.…”

Symbiotic fungal endophytePhomopsis liquidambari-rice system promotes nitrogen transformation by influencing below-ground straw decomposition in paddy soil

“…, ; Siddikee et al . ). A unified endophyte–crop–soil system might be proposed to influence below‐ground behaviour in agricultural ecosystems; however, the effectiveness of this system should be investigated.…”