Cloning and characterization of HsfA2 from Lily (Lilium longiflorum)

Abstract

Heat shock transcription factors (Hsfs) are the terminal components of the signal transduction chain mediating the activation of genes responsive to both heat stress and a large number of chemical stressors. This paper aims to clone Hsf from lily and characterize its function by analyses of mRNA expression, transactivation activity and thermotolerance of transgenic Arabidopsis. In this study, the gene encoding HsfA2 with 1,053 bp open reading frame (ORF) was cloned by rapid amplification of cDNA ends (RACE) technique from Lilium longiflorum 'White heaven'. Multiple alignment and phylogenetic analyses showed that the deduced protein was a novel member of the Hsf class A2. Expression analyses by RT-PCR indicated that LlHsfA2 expression was induced by heat shock and H(2)O(2) treatment, but not by NaCl. It was also found that the expression of LlHsfA2 correlated with thermotolerance in Lilium longiflorum 'White heaven' and Oriental hybrid 'Acapulco' under heat stress. Furthermore, yeast one-hybrid assay showed that LlHsfA2 had transactivation activity. In addition, overexpression of LlHsfA2 activated the downstream genes including Hsp101, Hsp70, Hsp25.3 and Apx2 and enhanced the thermotolerance of transgenic Arabidopsis plants. Taken together, our data suggest that LlHsfA2 is a novel and functional HsfA2, involved in heat signaling pathway in lily and useful for improvement of thermotolerance in transgenic plants.

Evaluation of putative reference genes for quantitative real-time PCR normalization inLilium regaleduring development and under stress

“…The selection of reference gene(s) might influence the results or even conclusion of studies, especially those concerning plant development or stress response, as there would be more variation in gene expression under those conditions. As a commonly used reference gene, the ACT gene family associated with cell structure maintenance was previously used as the reference gene for normalization in Lilium (Wang et al, 2009; Xin et al, 2010), and it showed stable expression in L. davidii var. unicolor (Li et al, 2015).…”

“…Thousands of cultivars in this genus were produced under inter-specific hybridization and artificial selection in the last twenty years. However, only a limited number of studies have been carried out on the gene expression of Lilium , and the reference genes used in these studies, namely ACT , 18S rRNA or GAPDH (He et al, 2014; Li et al, 2014; Tong et al, 2013; Wang et al, 2009; Xin et al, 2010), was only based on the results from other species without an experimental comparison among the candidate reference genes of Lilium . Only until very recently the evaluation of reference genes in L. davidii var.…”

Cloning and expression analysis of heat-shock transcription factor gene CaHsfA2 from pepper (Capsicum annuum L.)

“…The expression level in the heat-sensitive line B6 was higher than that in the heat-tolerant line R9 as a whole, which was not coherent with the heat tolerance ( Figure 5). Xin et al (2010) found that the HsfA2 expression in heat-tolerant cultivar leaves of Lilium longiflorum reached its peak 1 h after the heat treatment, and then it decreased slightly. In contrast, in the heat-sensitive cultivar, the expression peaked 12 h after the heat shock and then decreased significantly.…”

“…All of these are important for the formation of plant thermotolerance (Schramm et al, 2006). Until now, the function of the gene HsfA2 in thermotolerance formation has been researched in Solanum lycopersicum (Scharf et al, 1993), Arabidopsis thaliana (Charng et al, 2007), Oryza sativa (Yokotani et al, 2008), and Lilium longiflorum (Xin et al, 2010).…”

Aspects of bulblet growth of lily in vitro

“…The moderate HAT stress may activate some thermo-tolerance genes to protect against severe HAT. A heat shock transcription factor gene called LlHsfA2, has been reported to play an important role in heat signalling pathway in lily and it has been demonstrated that overexpression of LlHsfA2 can increase the thermotolerance of transgenic Arabidopsis plants (Xin et al, 2010). This observation is strengthened by the fact that LlHSFA1 isolated from lily leaves and overexpressed in transgenic Arabidopsis gave similar results (Gong et al, 2014).…”