Int. J. Mol. Sci. 2013, 14(12), 24008-24028; doi:10.3390/ijms141224008
Article

Antioxidant Enzymatic Activities and Gene Expression Associated with Heat Tolerance in the Stems and Roots of Two Cucurbit Species (“Cucurbita maxima and Cucurbita moschata”) and Their Interspecific Inbred Line Maxchata

1 Laboratory of Genetic Resources & Functional Improvement for Horticultural Plants, Department of Horticulture, Zhejiang University, Hangzhou 310058, China 2 Key Laboratory of Horticultural Plant Growth, Development & Quality Improvement, Ministry of Agriculture, Hangzhou 310058, China 3 Department of Plant Science, Faculty of Natural Resources, Prince of Songkhla University, Hat Yai, Songkhla 90112, Thailand
* Author to whom correspondence should be addressed.
Received: 9 October 2013; in revised form: 15 November 2013 / Accepted: 28 November 2013 / Published: 10 December 2013
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
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Abstract: The elucidation of heat tolerance mechanisms is required to combat the challenges of global warming. This study aimed to determine the antioxidant enzyme responses to heat stress, at the enzymatic activity and gene expression levels, and to investigate the antioxidative alterations associated with heat tolerance in the stems and roots of squashes using three genotypes differing in heat tolerance. Plants of heat-tolerant “C. moschata”, thermolabile “C. maxima” and moderately heat-tolerant interspecific inbred line “Maxchata” genotypes were exposed to moderate (37 °C) and severe (42 °C) heat shocks. “C. moschata” exhibited comparatively little oxidative damage, with the lowest hydrogen peroxide (H2O2), superoxide (O2) and malondialdehyde (MDA) contents in the roots compared to stems, followed by “Maxchata. The enzyme activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) were found to be increased with heat stress in tolerant genotypes. The significant inductions of FeSOD, MnSOD, APX2, CAT1 and CAT3 isoforms in tolerant genotypes suggested their participation in heat tolerance. The differential isoform patterns of SOD, APX and CAT between stems and roots also indicated their tissue specificity. Furthermore, despite the sequence similarity of the studied antioxidant genes among “C. maxima and “Maxchata”, most of these genes were highly induced under heat stress in “Maxchata”, which contributed to its heat tolerance. This phenomenon also indicated the involvement of other unknown genetic and/or epigenetic factors in controlling the expression of these antioxidant genes in squashes, which demands further exploration.
Keywords: squashes; heat stress; oxidative stress; pumpkin; thermotolerance; transcript levels

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MDPI and ACS Style

Ara, N.; Nakkanong, K.; Lv, W.; Yang, J.; Hu, Z.; Zhang, M. Antioxidant Enzymatic Activities and Gene Expression Associated with Heat Tolerance in the Stems and Roots of Two Cucurbit Species (“Cucurbita maxima and Cucurbita moschata”) and Their Interspecific Inbred Line Maxchata”. Int. J. Mol. Sci. 2013, 14, 24008-24028.

AMA Style

Ara N, Nakkanong K, Lv W, Yang J, Hu Z, Zhang M. Antioxidant Enzymatic Activities and Gene Expression Associated with Heat Tolerance in the Stems and Roots of Two Cucurbit Species (“Cucurbita maxima and Cucurbita moschata”) and Their Interspecific Inbred Line Maxchata”. International Journal of Molecular Sciences. 2013; 14(12):24008-24028.

Chicago/Turabian Style

Ara, Neelam; Nakkanong, Korakot; Lv, Wenhui; Yang, Jinghua; Hu, Zhongyuan; Zhang, Mingfang. 2013. "Antioxidant Enzymatic Activities and Gene Expression Associated with Heat Tolerance in the Stems and Roots of Two Cucurbit Species (“Cucurbita maxima and Cucurbita moschata”) and Their Interspecific Inbred Line Maxchata”." Int. J. Mol. Sci. 14, no. 12: 24008-24028.

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