Autophagy-related gene, TdAtg8, in wild emmer wheat plays a role in drought and osmotic stress response

Abstract

An autophagy-related gene Atg8 was cloned for the first time from wild emmer wheat, named as TdAtg8, and its role on autophagy under abiotic stress conditions was investigated. Examination of TdAtg8 expression patterns indicated that Atg8 expression was strongly upregulated under drought stress, especially in the roots when compared to leaves. LysoTracker(®) red marker, utilized to observe autophagosomes, revealed that autophagy is constitutively active in Triticum dicoccoides. Moreover, autophagy was determined to be induced in plants exposed to osmotic stress when compared to plants grown under normal conditions. Functional studies were executed in yeast to confirm that the TdATG8 protein is functional, and showed that the TdAtg8 gene complements the atg8∆::kan MX yeast mutant strain grown under nitrogen deficiency. For further functional analysis, TdATG8 protein was expressed in yeast and analyzed using Western immunoblotting. Atg8-silenced plants were exposed to drought stress and chlorophyll and malondialdehyde (MDA) content measurements demonstrated that Atg8 plays a key role on drought stress tolerance. In addition, Atg8-silenced plants exposed to osmotic stress were found to have decreased Atg8 expression level in comparison to controls. Hence, Atg8 is a positive regulator in osmotic and drought stress response.

Autophagic Recycling Plays a Central Role in Maize Nitrogen Remobilization

“…Whereas most of our current understanding comes from Arabidopsis, recent studies have also begun to focus on crop species to understand its consequences to nutrient management and agronomic yield. This study and that by Chung et al (2009) with maize along with parallel work in rice (Xia et al, 2011;Kurusu et al, 2014), wheat (Kuzuoglu-Ozturk et al, 2012), and tomato (Solanum lycopersicum; Zhou et al, 2014) revealed that a mechanistically similar autophagic system exists in crops and that most genes within the pathway are tightly regulated transcriptionally during development, are activated by nutrient limitation and other stresses, and are upregulated during leaf senescence. Unfortunately, the male-sterile phenotype of the first rice atg mutant described that eliminated ATG7 (Kurusu et al, 2014) limited an appreciation of autophagy with respect to N economy and yield.…”

Drought resistance of wheat alien chromosome addition lines evaluated by membership function value based on multiple traits and drought resistance index of grain yield

“…One opportunity is presented by the exploitation of wild germplasm of wheat. Triticum dicoccoides is an important source of drought-related genes and is highly suitable as a donor for improving drought resistance in cultivated wheat species (Peleg et al, 2008;Peng et al, 2013); several drought tolerance genes of T. dicoccoides have been identified and characterized (Lucas et al, 2011a,b;Kuzuoglu-Ozturk et al, 2012). It seemed that the interspecies variations are more profound than intraspecies variations.…”

Methods for analysis of autophagy in plants

“…In addition, autophagy seems to play a role in pathogen defense responses [25][26][27][28][29] and is required for appropriate nutrient remobilization during leaf senescence [19,[30][31][32]. Autophagy is now beginning to be studied in additional plant species, particularly in agriculturally-important crop species in which stress tolerance and defense are critical for optimizing yield [33][34][35][36][37].…”