Molecular cloning and functional analysis of the drought tolerance gene MsHSP70 from alfalfa (Medicago sativa L.)
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Heat shock proteins (HSPs) are a ubiquitously expressed class of protective proteins that play a key role in plant response to stressful conditions. This study aimed to characterize and investigate the function of an HSP gene in alfalfa (Medicago sativa). MsHSP70, which contains a 2028-bp open reading frame, was identified through homology cloning. MsHSP70 shares high sequence identity (94.47%) with HSP70 from Medicago truncatula. Expression analysis of MsHSP70 in alfalfa organs revealed a relatively higher expression level in aerial organs such as flowers, stems and leaves than in roots. MsHSP70 was induced by heat shock, abscisic acid (ABA) and hydrogen peroxide. Transgenic Arabidopsis seedlings overexpressing MsHSP70 were hyposensitive to polyethylene glycol (PEG) and ABA treatments, suggesting that exogenous expression of MsHSP70 enhanced Arabidopsis tolerance to these stresses. Examination of physiological indexes related to drought and ABA stress demonstrated that in comparison with non-transgenic plants, T3 transgenic Arabidopsis plants had an increased proline content, higher superoxide dismutase (SOD) activity, and decreased malondialdehyde (MDA) content. Furthermore, higher relative water content (RWC) was detected in transgenic plants compared with non-transgenic plants under drought stress. These findings clearly indicate that molecular manipulation of MsHSP70 in plants can have substantial effects on stress tolerance.
KeywordsHeat shock protein Medicago sativa Stress response Transgenic Arabidopsis
Heat shock protein
Relative water content
Open reading frame
Green fluorescent protein
Quantitative real-time PCR
This work was supported by the National Program on Key Basic Research Project (Grant Number: 2014CB138703-2), the China Agriculture Research System (Grant Number: CARS-35-04) and The Agricultural Science and Technology Innovation Program (Grant Number: ASTIP-IAS14).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
- Asada K, Foyer CH, Mullineaux PM (1994) Production and action of active oxygen species in photosynthetic tissues. Causes Photooxidative Stress Aamelioration Def Syst Plants 77–104.Google Scholar
- Cazalé AC, Clément M, Chiarenza S, Roncato MA, Pochon N, Creff A, Marin E, Leonhardt N, Noël LD (2009) Altered expression of cytosolic/nuclear HSC70-1 molecular chaperone affects development and abiotic stress tolerance in Arabidopsis thaliana. J Exp Bot 60:2653–2664. doi: 10.1093/jxb/erp109 CrossRefPubMedGoogle Scholar
- Clough SJ, Bent AF (1998) Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana. Plant Journal 16:735–743. 10.1046/j.1365-313x.1998.00343.xGoogle Scholar
- Kanzaki H, Saitoh H, Ito A, Fujisawa S, Kamoun S, Katou S, Yoshioka H, Terauchi R (2003) Cytosolic HSP90 and HSP70 are essential components of INF1-mediated hypersensitive response and non-host resistance to pseudomonas cichorii in nicotiana benthamiana. Mol Plant Pathol 4:383–391. doi: 10.1046/j.1364-3703.2003.00186.x CrossRefPubMedGoogle Scholar
- Lee S, Lee DW, Lee Y, Mayer U, Stierhof Y-D, Lee S, Jürgens G, Hwang I (2009) Heat shock protein cognate 70–4 and an E3 ubiquitin ligase, CHIP, mediate plastid-destined precursor degradation through the ubiquitin-26S proteasome system in Arabidopsis. Plant Cell 21:3984–4001. doi: 10.1105/tpc.109.071548 CrossRefPubMedPubMedCentralGoogle Scholar
- Matysik J, Bhalu B, Mohanty P (2002) Molecular mechanisms of quenching of reactive oxygen species by proline under stress in plants. Current Science 82:525–532Google Scholar
- Montero-Barrientos M, Hermosa R, Cardoza RE, Gutiérrez S, Nicolás C, Monte E (2010) Transgenic expression of the Trichoderma harzianum hsp70 gene increases Arabidopsis resistance to heat and other abiotic stresses. J Plant Physiol 167:659–665. doi: 10.1016/j.jplph.2009.11.012 CrossRefPubMedGoogle Scholar
- Panthee DR, Yuan JS, Wright DL, Marois JJ, Mailhot D, Stewart CN Jr (2007) Gene expression analysis in soybean in response to the causal agent of Asian soybean rust (Phakopsora pachyrhizi Sydow) in an early growth stage. Funct Integr Genomics 7:291–301. doi: 10.1007/s10142-007-0045-8 CrossRefPubMedGoogle Scholar