Constitutive Expression of a Tomato Small Heat Shock Protein Gene LeHSP21 Improves Tolerance to High-Temperature Stress by Enhancing Antioxidation Capacity in Tobacco

Abstract

It is well established that small heat shock proteins (sHSPs) play an important role in thermotolerance in various organisms due to their abundance and diversity. In the present study, a chloroplast small heat shock protein gene (LeHSP21) from tomato (Lycopersicon esculentum cv PKM-1) was constitutively expressed in tobacco (Nicotiana tabacum L. cv Wisconsin 38) plants via Agrobacterium-mediated transformation. When compared to wild-type control plants, transgenic tobacco plants constitutively expressing LeHSP21, driven by the cauliflower mosaic virus 35S promoter, exhibited improved tolerance to both high temperature and oxidative stress. Furthermore, when the seedlings were subjected to high temperature treatment, the activities of anti-oxidative enzymes and the content of proline were significantly higher in transgenic plants than those in the wild-type plants. Our results presented here demonstrate the feasibility of improving high temperature and oxidative stress tolerance in plants through the expression of LeHSP21 gene.

Subtly Manipulated Expression of ZmmiR156 in Tobacco Improves Drought and Salt Tolerance Without Changing the Architecture of Transgenic Plants

“…Upon treatment with drought or salt stress, proline accumulated to a significantly higher level in both 35S:: ZmmiR156 and Rab17::MIR156 transgenic plants than in wild type and vector control plants (Figures 2E, 3E, and 4D, I). This is consistent with previous reports that transgenic salt tolerant plants accumulated more proline (Nanjo et al, 1999;Zhang and Blumwald, 2001;Zhang et al, 2016). Therefore, the augmented proline accumulation in transgenic plants may have helped protect the activity of antioxidative enzymes and as a result alleviated the adverse impacts imposed by drought and salt on transgenic plants.…”

“…Therefore, we postulated that under adverse growth conditions, expression of ZmmiR156 helped protect cell membrane integrity in transgenic plants. This hypothesis was also supported by the observations of transgenic tobacco expressing inositol polyphosphate 6-/3kinase AtIpk2b and heat shock protein LeHSP21 (Yang et al, 2008;Zhang et al, 2016).…”

Exogenously applied growth regulators protect the cotton crop from heat-induced injury by modulating plant defense mechanism

“…High temperature at three reproductive stages of cotton increased ROS e.g. lipid membrane peroxidation contents (MDA) which may affect the cell organelles as documented by 25 . A constricted balance between ROS and antioxidant enzymes is required 26 , 27 but the stress conditions affected this balance between chloroplasts or mitochondria.…”

“…The present findings were supported by 4 , 28 . High temperature stress reduced chlorophyll contents and photosynthetic rate in tomato leaves 25 which might be due to reduced CO 2 fixation and photosynthesis process 29 , 30 . Relatively lower chlorophyll contents and net photosynthetic rate was observed in sub and supra-optimal thermal regimes of glass house and under high temperature regimes of field study at three reproductive stages of cotton crop might be due to higher oxidative stress.…”

Genome-Wide Identification and Expression Profiling of Tomato Hsp20 Gene Family in Response to Biotic and Abiotic Stresses

“…To date, the Hsp20 gene families have been investigated in several plant species, including Arabidopsis , rice, soybean, pepper, and Populus trchocarpa (Scharf et al, 2001 ; Waters et al, 2008 ; Ouyang et al, 2009 ; Sarkar et al, 2009 ; Lopes-Caitar et al, 2013 ; Guo et al, 2015 ). In addition, some key features of Hsp20 and biologic function of several Hsp20 genes had been identified (Nautiyal and Shono, 2010 ; Goyal et al, 2012 ; Huther et al, 2013 ; Mahesh et al, 2013 ; Arce et al, 2015 ; Zhang et al, 2016 ). Although the availability of the tomato whole-genome sequence provides valuable resources for getting into an in-depth understanding of Hsp20s (Sato et al, 2012 ), little information is available on the integrated Hsp20 family at whole genomic level in tomato.…”