Exogenous Auxin-Mediated Salt Stress Alleviation in Faba Bean (Vicia faba L.)

Arafat Abdel Hamed Abdel Latef,Md Tahjib-Ul-Arif,Mohammad Saidur Rhaman

doi:10.3390/agronomy11030547

Arafat Abdel Hamed Abdel Latef, Md Tahjib-Ul-Arif + Show 1 more

Open Access

https://doi.org/10.3390/agronomy11030547

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Journal: Agronomy	Publication Date: Mar 14, 2021
Citations: 40	License type: CC BY 4.0

Affiliation: Taif University, Bangladesh Agricultural University

Abstract

Auxin not only controls the development processes, but also regulates the stress responses of plants. In this investigation, we explored the potential roles of exogenously applied indole-3-acetic acid (IAA) in conferring salt tolerance in the faba bean (Vicia faba L.). Our results showed that foliar application of IAA (200 ppm) to salt-exposed (60 mM and 150 mM NaCl) plants promoted growth, which was evidenced by enhanced root–stem traits. IAA application ensured better osmotic protection in salt-stressed plants which was supported by reduced proline and enhanced soluble sugar, soluble protein, and total free amino acid contents in the roots, stem, and seeds. IAA application also increased the number of nodules in salt-stressed plants, which may facilitate better nitrogen assimilation. Moreover, IAA mediated improvements in mineral homeostasis (K+, Ca2+, and Mg2+) and the translocation of Na+, while it also inhibited excessive accumulation of Na+ in the roots. Salt-induced oxidative damage resulted in increased accumulation of malondialdehyde, whereas IAA spraying relegated malondialdehyde by improving antioxidant enzymes, including superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase. Together, these results together with a principal component analysis uncovered that foliar spraying of IAA alleviated the antagonistic effects of salt stress via enhancing osmolyte accumulation, ionic homeostasis, and antioxidant activity. Finally, exogenous IAA enhanced the yield of broad beans under high salinity conditions.

Highlights

The existence of excessive levels of salts in agricultural fields is a serious current global issue that severely hampers crop production [1]
We found that salt stress increased total soluble sugars (TSS), total free amino acid (TFAA), and Pro contents in different organs of V. faba plants and exogenous application of indole-3-acetic acid (IAA) boosted TSS, total soluble proteins (TSP), and TFAA contents and decreased Pro content in salt-stressed plants (Figure 2), with the principal component analysis (PCA) analysis validating the strong positive correlation of these osmolytes with the IAA + S1 and IAA + S2 treatments (Figure 6)
These results indicate that IAA enhances the TSP, TSS, and TFAA contents in plants and that increased osmolytes in the stressed V. faba plants may enable plants to reduce the energy required for growth and survival via enabling better osmotic adjustment

Summary

Introduction

The existence of excessive levels of salts in agricultural fields is a serious current global issue that severely hampers crop production [1]. Recent reports show that approximately 0.80 billion hectares of terrestrial areas are disturbed by salts and this substantially limits the use of land for agricultural purposes [2,3]. About 20% of the crop-cultivable area and about 33% of irrigated crop-land are affected by salinity levels to varying degrees, and by 2050, this figure will exceed 50% [2,4]. At a later stage, salinity-exposed plants experience enhanced oxidative stress because of the production of excessive amounts of reactive oxygen species (ROS). ROS production results in oxidative injuries to different cellular macromolecules, including lipids, proteins, and nucleic acids, which disrupts many important cellular processes in plants [1,6,7]

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Conclusion