Inoculation With Piriformospora indica Is More Efficient in Wild-Type Rice Than in Transgenic Rice Over-Expressing the Vacuolar H+-PPase

Abstract

Achieving food security in a context of environmental sustainability is one of the main challenges of the XXI century. Two competing strategies to achieve this goal are the use of genetically modified plants and the use of plant growth promoting microorganisms (PGPMs). However, few studies assess the response of genetically modified plants to PGPMs. The aim of this study was to compare the response of over-expressing the vacuolar H + -PPase (AVP) and wild-type rice types to the endophytic fungus; Piriformospora indica . Oryza sativa plants (WT and AVP) were inoculated with P. indica and 30 days later, morphological, ecophysiological and bioenergetic parameters, and nutrient content were assessed. AVP and WT plant heights were strongly influenced by inoculation with P. indica , which also promoted increases in fresh and dry matter of shoot in both genotypes. This may be related with the stimulatory effect of P. indica on ecophysiological parameters, especially photosynthetic rate, stomatal conductance, intrinsic water use efficiency and carboxylation efficiency. However, there were differences between the genotypes concerning the physiological mechanisms leading to biomass increment. In WT plants, inoculation with P. indica stimulated all H + pumps. However, in inoculated AVP plants, H + -PPase was stimulated, but P- and V-ATPases were inhibited. Fungal inoculation enhanced nutrient uptake in both shoots and roots of WT and AVP plants, compared to uninoculated plants; but among inoculated genotypes, the nutrient uptake was lower in AVP than in WT plants. These results clearly demonstrate that the symbiosis between P. indica and AVP plants did not benefit those plants, which may be related to the inefficient colonization of this fungus on the transgenic plants, demonstrating an incompatibility of this symbiosis, which needs to be further studied.

Epiphytic fungi induced pathogen resistance of invasive plant Ipomoea cairica against Colletotrichum gloeosporioides

“…Symbiosis between plants and microbes is a very common ecological relationship. Host plants obtain diverse benefits from the symbiosis involving the improvement of nutrition availability (Bertolazi et al, 2019), yields (Xia et al, 2016) and tolerance against abiotic as well as biotic stresses (Daneshkhah, Grundler & Wieczorek, 2018;Song et al, 2015). In this study, the occurrence rates of F. oxysporum and F. fujikuroi on leaf surface of I. cairica reached up to 100% regardless of habitat.…”

The Free-Living Stage Growth Conditions of the Endophytic Fungus Serendipita indica May Regulate Its Potential as Plant Growth Promoting Microbe

“…Glucose availability is known to play an important role in the modulation and expression of P-H + -ATPase in yeast ( Eraso and Gancedo, 1987 ; Portillo, 2000 ) and in filamentous fungi, including basidiomycetes ( Ramos et al, 2005 ; Kralj Kuncic et al, 2013 ). Regarding fungi capable of associating with plants, although there is little information on the effect of glucose availability on P-H + -ATPase, both AMF- ( Liu et al, 2016 ; Lopez-Coria et al, 2016 ; Aloui et al, 2018 ) and S. indica -colonised plants ( Bertolazi et al, 2019 ) have shown increased nutrient uptake due to the increase in activity and expression of these proton pumps.…”

“…Twenty root segments of 1 cm length were randomly chosen from each treatment and examined under a light microscope. Root colonisation was determined using the following formula: Root colonisation (%) = [(number of colonised segments/total number of segments examined) × 100] (Bertolazi et al, 2019).…”

“…The endophytic fungus Serendipita indica (former Piriformospora indica) fulfils the abovementioned advantages over AMF, and displays a high versatility of association with plants (Varma et al, 1999;Bertolazi et al, 2019;Heidarianpour et al, 2020;Leyva-Rojas et al, 2020). Further, S. indica grows inter-and intracellularly and forms a spiral structure similar to AMF's arbuscules, creating a symbiotic interface in the space between fungal hyphae and the cell wall (Schäfer and Kogel, 2009).…”

Epiphytic fungi induced pathogen resistance of invasive plant Ipomoea cairica against Colletotrichum gloeosporioides

“…The occurrence, abundance and pathogen resistance attributes of F. oxysporum and F. fujikuroi Symbiosis between plants and microbes is a very common ecological relationship. Host plants obtain diverse benefits from the symbiosis involving the improvement of nutrition availability (Ngwene et al, 2016;Bertolazi et al, 2019), yields (Xia et al, 2016 and tolerance against abiotic as well as biotic stresses (Daneshkhah, Grundler & Wieczorek, 2018;Song et al, 2015). In this study, the occurrence rates of F. oxysporum and F. fujikuroi on leaf surface of I. cairica reached up to 100% regardless of habitat.…”