title: Regulation of some carbohydrate metabolism-related genes, starch and soluble sugar contents, photosynthetic activities and yield attributes of two contrasting rice genotypes subjected to salt stress.
abstract: Soluble carbohydrates play a key role as osmolytes and significantly contribute in salt defence mechanism, especially in halophyte species. The objective of this study is to investigate the transcriptional expression of starch-related genes, sugar profile and physiological performances of two contrasting rice genotypes, Pokkali (salt tolerant) and IR29 (salt sensitive), in response to salt stress. Total soluble sugars, glucose and fructose levels in the flag leaf of salt-stressed Pokkali rice were enhanced relative to soluble starch accumulation in plants exposed to EC = 13.25 dS m(-1) (salt stress) for 3 days. In Pokkali, the net photosynthetic rate and starch metabolism may play a key role as energy resources under salt stress. In contrast, photosynthetic performance, indicated by photosynthetic pigment levels and chlorophyll fluorescence parameters, in salt-stressed IR29 was significantly reduced, leading to delayed starch biosynthesis. The reduction in photosynthetic ability and lack of defence mechanisms in IR29 caused growth inhibition and yield loss. Soluble starch and soluble sugar enrichment in Pokkali rice may function alternatively as osmotic adjustment in salt defence mechanism and strengthen carbon energy reserves, greater survival prospects under salt stress and enhanced productivity.
authors.affiliation: Department of Biotechnology, Faculty of Science, Mahidol University, Payathai, Bangkok, 10400, Thailand.
authors.forename: Thanaphol
authors.initials: T
authors.lastname: Boriboonkaset
authors.forename: Cattarin
authors.initials: C
authors.lastname: Theerawitaya
authors.forename: Nana
authors.initials: N
authors.lastname: Yamada
authors.forename: Aussanee
authors.initials: A
authors.lastname: Pichakum
authors.forename: Kanyaratt
authors.initials: K
authors.lastname: Supaibulwatana
authors.forename: Suriyan
authors.initials: S
authors.lastname: Cha-Um
authors.forename: Teruhiro
authors.initials: T
authors.lastname: Takabe
authors.forename: Chalermpol
authors.initials: C
authors.lastname: Kirdmanee
mesh_terms: D050260:Carbohydrate Metabolism / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005838:Genotype; D012275:Oryza / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D064587:Osmoregulation; D010788:Photosynthesis / Q000187:drug effects / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology; D013213:Starch / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
chemical_list: D012965:Sodium Chloride; D013213:Starch
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