Author:
Wu Yue,Li Jing,Wang Junwen,Dawuda Mohammed Mujitaba,Liao Weibiao,Meng Xin,Yuan Hong,Xie Jianming,Tang Zhongqi,Lyu Jian,Yu Jihua
Abstract
AbstractA biosynthetic precursor of tetrapyrrol, 5-aminolevulinic acid (ALA), is widely used in agricultural production, as an exogenous regulatory substance that effectively regulates plant growth. Previous studies have shown that heme and chlorophyll accumulate in plants under salt stress, when treated with exogenous ALA. In this study, we explored the regulatory role of heme in plants, by spraying 25 mg L–1 ALA onto the leaves of cucumber seedlings treated with heme synthesis inhibitor (2,2'-dipyridyl, DPD) and heme scavenger (hemopexin, Hx), under 50 mmol L–1 NaCl stress. The results showed that NaCl alone and DPD + Hx treatments to cucumber seedlings subjected to salt stress adversely affected their growth, by decreasing biomass accumulation, root activity, and root morphology. In addition, these treatments induced an increase in membrane lipid oxidation, as well as enhancement of anti-oxidase activities, proline content, and glutamate betaine. However, exogenous ALA application increased the plant growth and root architecture indices under NaCl stress, owing to a lack of heme in the seedlings. In addition, cucumber seedlings treated with DPD and Hx showed inhibition of growth under salt stress, but exogenous ALA effectively improved cucumber seedling growth as well as the physiological characteristics; moreover, the regulation of ALA in plants was weakened when heme synthesis was inhibited. Heme biosynthesis and metabolism genes, HEMH and HO1, which are involved in the ALA metabolic pathway, were upregulated under salinity conditions, when ferrochelatase activity was inhibited. Application of exogenous ALA increased the heme content in the leaves. Thus, exogenous ALA may supplement the substrates for heme synthesis. These results indicated that heme plays a vital role in the response of plants to salinity stress. In conclusion, heme is involved in ALA-mediated alleviation of damage caused to cucumber seedlings and acts as a positive regulator of plant adaption.
Funder
Natural Science Foundation of Gansu Province
Education science and technology innovation project of Gansu Province
National Natural Science Foundation of China
Agriculture Research System of China
Special Project of Central Government Guiding Local Science and Technology Development
Publisher
Springer Science and Business Media LLC
Reference74 articles.
1. Mathur S, Agrawal D, Jajoo A. Photosynthesis: response to high temperature stress. J Photochem Photobiol, B. 2014;137:116–26.
2. Yu L, Yan J, Yang Y, Zhu W. Overexpression of tomato mitogen-activated protein kinase SlMPK3 in tobacco increases tolerance to low temperature stress. Plant Cell Tissue Organ Culture (PCTOC). 2015;121(1):21–34.
3. Chemaly ER, Kang S, Zhang S, Mccollum LT, Chen J, Bénard L, Purushothaman K, Hajjar RJ, Lebeche D. Genetic gains in grain yield through genomic selection in eight bi-parental maize populations under drought stress. J Physiology. 2015;591(21):5337–5355.
4. Saijo Y, Hata S, Kyozuka J, Shimamoto K, Izui K. Over-expression of a single Ca2+-dependent protein kinase confers both cold and salt/drought tolerance on rice plants. Plant J. 2000;23(3):319–27.
5. Wang LJ, Jiang WB, Huang BJ. Promotion of 5-aminolevulinic acid on photosynthesis of melon (Cucumis melo) seedlings under low light and chilling stress conditions. Physiol Plant. 2004;121(2):258–64.