Improved tolerance of wheat plants (Triticum aestivum L.) to drought stress and rewatering by the arbuscular mycorrhizal fungus Glomus claroideum: effect on growth and cell membrane stability

Abstract

The aim of this paper was to investigate the contribution of the arbuscular mycorrhizal fungus Glomus claroideum to drought stress tolerance in wheat plants grown under controlled conditions in a growth chamber, and subjected to moderate or severe water stress and rewatering. Water stress tolerance was determined through total dry weight, leaf relative water content, leakage of solutes and leaf chlorophyll and protein concentrations in mycorrhizal and nonmycorrhizal wheat plants. Total dry weight and leaf chlorophyll concentrations were significantly higher in mycorrhizal plants after moderate or severe water stress treatments compared with non-mycorrhizal ones. Electrolyte leakage was significantly lower in water-stressed inoculated plants. Compared to non-inoculated plants, leaf relative water content and total protein concentration of inoculated individuals increased only under severe water stress. When irrigation was re-established, mycorrhizal plants increased their total dry weight and leaf chlorophyll concentration, and recovered cell membrane permeability in leaves compared with non-mycorrhizal plants. In conclusion, root colonization by G. claroideum could be an adequate strategy to alleviate the deleterious effects of drought stress and retard the senescence syndrome in wheat. Key words: mycorrhizae, relative water content, rewatering, solute leakage, water deficit A melhoria da tolerância do trigo (Triticum aestivum L.) ao estresse hídrico e à reidratação pelo fungo micorrízico arbuscular (Glomus claroideum): Efeito sobre o crescimento e estabilidade das membranas celulares: O objetivo do trabalho foi pesquisar a contribuição do fungo micorrízico arbuscular Glomus claroideum à tolerância ao déficit hídrico em plantas de trigo cultivadas sob condições controladas em uma câmara de crescimento, submetidas ao estresse hídrico moderado ou severo e reidratação. A tolerância das plantas ao estresse hídrico foi determinada mediante o peso seco total, conteúdo relativo de água foliar, extravasamento de solutos e concentrações foliares de clorofilas e proteínas totais nas plantas de trigo micorrizadas e não-micorrizadas. O peso seco total e a concentração de clorofila foram significativamente maiores nas plantas micorrizadas sob estresse hídrico moderado ou severo, quando comparadas com as não-micorrizadas. O extravasamento de solutos foi significativamente menor nas plantas inoculadas estressadas. O conteúdo relativo de água foliar e a concentração de proteínas totais nas plantas inoculadas aumentaram apenas em condições de estresse hídrico severo. Após a re-irrigação, nas plantas micorrizadas, houve aumento do peso seco total e da concentração de clorofilas, além da recuperação da integridade das membranas celulares, quando comparadas com as plantas não-micorrizadas. Em suma, a colonização das raízes por G. claroideum poderia ser uma estratégia adequada para reduzir os efeitos deletérios do estresse hídrico e retardar a síndrome da senescência em trigo. Palavras-chave: conteúdo relativo de água, déficit hídri...

Mycosphere Essay 17 Arbuscular mycorrhizal symbiosis and drought tolerance in crop plants

“…Although, in general, drought affects the AMF colonization negatively (Ryan and Ash 1996), in wheat AMF has been shown to alleviate the drought stress and increase yield mainly through improved nutrient uptake (Al -Karaki et al 2004). Claroideoglomus claroideum (=Glomus claroideum) seems to play a key role in imparting drought tolerance in wheat by improved chlorophyll content and cell membrane permeability (Beltrano and Ronco 2008). Effects of AMF on drought alleviation seem to also differ among genotypes of wheat (Al -Karaki and Al -Raddad, 1997).…”

“…A recent finding indicates that AMF play a key role in modifications of root hairs consequently helping the plants to overcome the drought (Li et al 2014). Besides helping the plants to explore larger volumes of soils for absorbing more water, AMF help the plants to maintain high relative water content (RWC) of the leaf, improves water use efficiency (WUE) (Beltrano et al 2003;Meddich et al 2015), increase leaf area, delay senescence (Beltrano and Ronco 2008) and maintain ion balance (Giri et al 2007). Furthermore, association also makes the plants to have greater osmotic adjustment through accumulation of osmolytes and more specifically, the proline.…”

Physio-Biochemical Responses of Oil Palm (Elaeis guineensisJacq.) Seedlings to Mannitol- and Polyethylene Glycol-Induced Iso-Osmotic Stresses

“…In this study, REL in oil palm seedlings was increased under PEG-and mannitol-induced osmotic stress, as was proline accumulation. REL in different plant species in response to water stress, has been shown to increase, depending on the degree of stress and the type of stressor (Bajji et al, 2001;Beltrano and Ronco, 2008;Chaum et al, 2010b;Xu and Huang, 2010).…”

Diversidade de fungos micorrízicos arbusculares em área de Caatinga, PE, Brasil

“…Os FMA promovem maior absorção de nutrientes, beneficiando o hospedeiro principalmente com a translocação do fósforo (He et al 2002),e também outros íons, proporcionam aumento da resistência vegetal contra patógenos (Liu et al 2007) e maior tolerância a estresses hídrico (Beltrano & Ronco 2008) e salino (Maia & Yano-Melo 2005), contribuindo ainda para a agregação do solo (Mergulhão et al 2010). Além disso, atuam na definição de nichos ecológicos ocupados pelos vegetais, determinando a composição das comunidades de plantas (Francis & Read 1995).…”