OsTPS8controls yield‐related traits and confers salt stress tolerance in rice by enhancing suberin deposition

Abstract

Class I TREHALOSE-PHOSPHATE-SYNTHASE (TPS) genes affect salinity tolerance and plant development. However, the function of class II TPS genes and their underlying mechanisms of action are unknown.We report the identification and functional analysis of a rice class II TPS gene (OsTPS8). The ostps8 mutant was characterised by GC-MS analysis, an abscisic acid (ABA) sensitivity test and by generating transgenic lines. To identify the underlying mechanism, gene expression analyses, genetic complementation and examination of suberin deposition in the roots were conducted.The ostps8 mutant showed salt sensitivity, ABA sensitivity and altered agronomic traits compared to the wild-type (WT), which could be rescued upon complementation. The dsRNAi line phenocopied the mutant, while the overexpression lines exhibited enhanced salt tolerance. The ostps8 mutant showed significantly reduced soluble sugars, Casparian bands and suberin deposition in the roots compared to the WT and overexpression lines. The mutant also showed downregulation of SAPKs (rice SnRK2s) and ABA-responsive genes. Furthermore, ostps8pUBI::SAPK9 rescued the salt-sensitive phenotype of ostps8.Our results suggest that OsTPS8 may regulate suberin deposition in rice through ABA signalling. Additionally, SAPK9-mediated regulation of altered ABA-responsive genes helps to confer salinity tolerance. Overexpression of OsTPS8 was adequate to confer enhanced salinity tolerance without any yield penalty, suggesting its usefulness in rice genetic improvement.

Root Physiological Traits and Transcriptome Analyses Reveal that Root Zone Water Retention Confers Drought Tolerance to Opisthopappus taihangensis

“…However, the function of class II TPS genes remains unclear. Recently, OsTPS8 overexpression lines conferred salt-stress tolerance in rice by enhancing suberin deposition 54 . This implies that class II TPS genes also play a crucial role in response to abiotic stress.…”

Characteristics and Expression Analyses of Trehalose-6-Phosphate Synthase Family in Prunus mume Reveal Genes Involved in Trehalose Biosynthesis and Drought Response

“…Based on TPS protein structure diversities of Class I and Class II, along with their function in complementing distinct TPS yeast mutants, Class II TPS members may function by distinct action modes from Class I proteins [ 23 , 24 ]. To explore the roles of Class II TPS members, several genes, including AtTPS6 [ 25 ], AtTPS5 [ 26 ], OsTPS8 [ 27 ], and TaTPS11 [ 28 ] have been cloned and characterized in detail. These genes can encode multifunctional enzymes with synthase and phosphatase activities, playing roles in plant architecture, stomatal closure, salt tolerance, and cold tolerance.…”

Trehalose 6-phosphate signalling and impact on crop yield

“…T6P levels change much more (over a 1000-fold range) than G6P and G1P [17,18], hence T6P provides more dynamic regulation of SnRK1 than could be achieved by G1P or G6P alone. The main factor that regulates T6P levels is sucrose [17,18]; T6P is therefore regarded as a sucrose signal, however, the impact of sucrose on T6P is attenuated by development and cell and tissue type [14,28]. Through SnRK1, T6P de-represses gene expression for carbon use in biosynthetic pathways enabling growth and development to proceed under conditions of sufficient carbon availability [9,18].…”

“…However, T6P levels did not differ in SUB1A compared with control so exact involvement of T6P in limiting underwater growth in SUB1A is not clear. OsTPS8 (OS08G0445700) was shown to confer salt stress tolerance by enhancing suberin deposition in roots [28]. Suberin is part of a hydrophobic barrier that blocks apoplastic leakage of ions into the xylem and damaging accumulation of Na + in shoots.…”

“…Specific genes are linked to traits where there is published evidence. OsTPS8 and OsTPP7 are [28] and [26], respectively. Improvement candidates in maize are from [44].…”