Wheat F-Box Protein Gene TaFBA1 Is Involved in Plant Tolerance to Heat Stress

Abstract

Adverse environmental conditions, including high temperature, often affect the growth and production of crops worldwide. F-box protein, a core component of the Skp1-Cullin-F-box (SCF) E3 ligase complex, plays an important role in abiotic stress responses. A previously cloned gene from wheat, TaFBA1, encodes a homologous F-box protein. A Yeast two-Hybrid (Y2H) assay showed that TaFBA1 interacted with other SCF proteins. We found that the expression of TaFBA1 could be induced by heat stress (45°C). Overexpression of TaFBA1 enhanced heat stress tolerance in transgenic tobacco, because growth inhibition was reduced and photosynthesis increased as compared with those in the wild type (WT) plants. Furthermore, the accumulation of H2O2, O2-, and carbonyl protein decreased and cell damage was alleviated in transgenic plants under heat stress, which resulted in less oxidative damage. However, the transgenic plants contained more enzymatic antioxidants after heat stress, which might be related to the regulation of some antioxidant gene expressions. The qRT-PCR analysis showed that the overexpression of TaFBA1 upregulated the expression of genes involved in reactive oxygen species (ROS) scavenging, proline biosynthesis, and abiotic stress responses. We identified the interaction of TaFBA1 with Triticum aestivum stress responsive protein 1 (TaASRP1) by Y2H assay and bimolecular fluorescence complementation (BiFC) assay. The results suggested that TaFBA1 may improve enzymatic antioxidant levels and regulate gene expression by interacting with other proteins, such as TaASRP1, which leads to the enhanced heat stress tolerance seen in the transgenic plants.

The involvement of wheat U‐box E3 ubiquitin ligase TaPUB1 in salt stress tolerance

“…Similar gene expression levels were also found in TaCu/Zn‐SOD (Figure I), TaFe‐SOD (Figure J) TaP5C (Figure L), TaCAT (Figure M), TaAPX (Figure O), and TaDHAR (Figure P); these are all antioxidant enzyme‐related genes (Feki et al 2014; Wang et al 2016b). But there was no remarkable change in the expression levels of TaFER‐5B (Figure G) (ROS accumulation‐related gene), TaSOD2 (Figure K) and TaPOD (Figure N) (antioxidant enzyme‐related genes) between transgenic and WT plants (Wang et al 2016a; Zang et al 2017; Li et al 2018). Thus, these results suggest that TaPUB1 increases salt stress tolerance by widely modulating the stress‐related transcriptional regulatory network.…”

“…The qPCR showed the different expression patterns of genes encoding antioxidant enzymes, TdMnSOD , TaCu/Zn‐SOD , TaFe‐SOD , TaP5C , TaCAT , TaAPX , and TaDHAR , in the transgenic wheat plants exposed to salt stress (Feki et al 2014; Kaouthar et al 2016; Wang et al 2016a; Wang et al 2016b; Zang et al 2017; Li, et al 2018). TaPUB1 enhanced the expressing level of these genes in TaPUB1‐OE plants (Figure ).…”

“…The Y2H assay was performed according to the Yeast Protocols Handbook (Clontech, Palo Alto, CA, USA). In the initial screening step, the full‐length TaPUB1 was used as a bait to screen a cDNA library made from wheat seedlings according to previous reports (Li et al 2018), using a screening kit (Clontech). The cDNA fragments of TaPUB1 and TaMP were inserted into the pGBKT7 (bait) and pGADT7 (prey) vectors, respectively.…”

“…The cDNA fragments of TaPUB1 and TaMP were inserted into the pGBKT7 (bait) and pGADT7 (prey) vectors, respectively. For the interaction assay, the bait and prey plasmids were cotransformed into the yeast strain Y2H gold, as previously described (Li et al 2018). The Y2H assay included the positive control (AD‐wXb12IP2 and BD‐wXb12) and negative control (AD‐wRAR1 and BD‐wXb12) (Cantu et al 2013).…”

Responses of young wheat plants to moderate heat stress

“…Proline may act as a signalling molecule to regulate mitochondrial functions, and it also modulates redox balance and energy status (Szabados and Savouré 2010). Accumulation of proline or other osmolytes may also alleviate osmotic stress induced by heat stress (Li et al 2018). Under the present experimental conditions, although the difference in the proline level between the wheat genotypes were not substantial, it was approx.…”