title: Differential changes in grain ultrastructure, amylase, protein and amino acid profiles between Tibetan wild and cultivated barleys under drought and salinity alone and combined stress.
abstract: Grain phytochemical profiles were compared in Tibetan wild barley XZ5 (drought-tolerant), XZ16 (salinity/aluminum-tolerant) and cv CM72 (salinity-tolerant) in response to drought and salinity alone and combination (D+S) during anthesis. Total antioxidant capacity assessed by determining ferric-reducing antioxidant potential (FRAP) in grains increased significantly as follows: D+S>drought>salinity, and XZ5>XZ16>CM72. A marked increase in the total phenol (TP) from individual and combined stresses was observed in XZ5, while a decrease occurred in CM72. Moreover, the activity of α-/β-amylase in the grains under combined stress was 81.8%/16.9% in XZ5 and 48.6%/18.7% in XZ16 higher than that of CM72. Increases in amino acids, protein content and protein fractions of albumin, globulin, hordein and glutelin were maximised under D+S, with larger values in the Tibetan wild genotypes. Observation with a scanning electron microscopy showed a distinct genotypic difference under D+S; for example, XZ5 and XZ16 maintained a relatively integral starch granule with a greater protein deposit/matrix, while CM72 degraded by pitting. This research expands our understanding of barley drought and salt-tolerance mechanisms and provides possibility of Tibetan wild barley in developing barley cultivars with both tolerance to drought and salinity.
authors.affiliation: Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China.
authors.forename: Imrul Mosaddek
authors.initials: IM
authors.lastname: Ahmed
authors.forename: Fangbin
authors.initials: F
authors.lastname: Cao
authors.forename: Yong
authors.initials: Y
authors.lastname: Han
authors.forename: Umme Aktari
authors.initials: UA
authors.lastname: Nadira
authors.forename: Guoping
authors.initials: G
authors.lastname: Zhang
authors.forename: Feibo
authors.initials: F
authors.lastname: Wu
mesh_terms: D000596:Amino Acids / Q000032:analysis* / Q000378:metabolism; D000975:Antioxidants / Q000032:analysis / Q000378:metabolism; D055864:Droughts; D001467:Hordeum / Q000737:chemistry* / Q000201:enzymology / Q000254:growth & development / Q000502:physiology; D019800:Phenol / Q000032:analysis / Q000378:metabolism; D010940:Plant Proteins / Q000032:analysis* / Q000378:metabolism; D054712:Salinity; D012639:Seeds / Q000737:chemistry* / Q000201:enzymology / Q000254:growth & development / Q000502:physiology; D013312:Stress, Physiological; D001614:beta-Amylase / Q000032:analysis* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D000975:Antioxidants; D010940:Plant Proteins; D019800:Phenol; D001614:beta-Amylase
keywords: Amino acid; Drought and salinity; Phenol; Starch granules; Tibetan wild barley (Hordeum vulgare L. ssp. spontaneum); Total antioxidant capacity (TAC)