Salt Stress Responses in Pigeon Pea (Cajanus cajan L.)

2018 ◽  
pp. 99-108
Author(s):  
Aditya Banerjee ◽  
Puja Ghosh ◽  
Aryadeep Roychoudhury

Cajanus cajan (L.) Millspaugh, known as pigeon pea, is considered a rustic legume, high-temperature tolerant, well adapted to environments with low water availability, saline, and low fertility soils. This study aimed to evaluate the germination and vigor of Cajanus cajan seeds under conditions of salt stress and different temperatures. A completely randomized experimental design was used, with treatments distributed in a 6 x 3 factorial scheme (salinity levels and temperatures), with four replications of 50 seeds. After determining the seed water content, the seeds were placed on germitest paper moistened with sodium chloride (NaCl) solutions in concentrations of 0.0 (control); 2.0; 4.0; 6.0; 8.0 and 10.0 dS m-1; Seeds were incubated in a B.O.D, at constant temperatures of 25 and 30 °C and alternating 20-30 ºC. The germination and vigor tests (first germination count, germination speed index, length and dry mass of roots and shots) were evaluated. An interaction between the salt concentration and temperature for all variables analyzed was observed, with a negative effect on the germination and vigor of Cajanus cajan seeds as the salinity levels increased. Salt stress simulated with NaCl reduced the germination and vigor of Cajanus cajan seeds, mainly when submitted to the temperature of 25 °C. However, the increase in NaCl concentration, up to the potential 10.0 dS m-1, was not high enough to impair seed germination.


2020 ◽  
Author(s):  
Ikeena Ohanenyw ◽  
XIaohong Sun ◽  
Chibuike Udenigwe

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiang Zhang ◽  
Yan Long ◽  
Jingjing Huang ◽  
Jixing Xia

Abstract Background Salt stress threatens crop yields all over the world. Many NAC transcription factors have been reported to be involved in different abiotic stress responses, but it remains unclear how loss of these transcription factors alters the transcriptomes of plants. Previous reports have demonstrated that overexpression of OsNAC45 enhances salt and drought tolerance in rice, and that OsNAC45 may regulate the expression of two specific genes, OsPM1 and OsLEA3–1. Results Here, we found that ABA repressed, and NaCl promoted, the expression of OsNAC45 in roots. Immunostaining showed that OsNAC45 was localized in all root cells and was mainly expressed in the stele. Loss of OsNAC45 decreased the sensitivity of rice plants to ABA and over-expressing this gene had the opposite effect, which demonstrated that OsNAC45 played an important role during ABA signal responses. Knockout of OsNAC45 also resulted in more ROS accumulation in roots and increased sensitivity of rice to salt stress. Transcriptome sequencing assay found that thousands of genes were differently expressed in OsNAC45-knockout plants. Most of the down-regulated genes participated in plant stress responses. Quantitative real time RT-PCR suggested that seven genes may be regulated by OsNAC45 including OsCYP89G1, OsDREB1F, OsEREBP2, OsERF104, OsPM1, OsSAMDC2, and OsSIK1. Conclusions These results indicate that OsNAC45 plays vital roles in ABA signal responses and salt tolerance in rice. Further characterization of this gene may help us understand ABA signal pathway and breed rice plants that are more tolerant to salt stress.


Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 547
Author(s):  
Arafat Abdel Hamed Abdel Latef ◽  
Md. Tahjib-Ul-Arif ◽  
Mohammad Saidur Rhaman

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.


Author(s):  
Yu Li ◽  
Hao Chen ◽  
Shengting Li ◽  
Cuiling Yang ◽  
Qunying Ding ◽  
...  

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kai Zhao ◽  
Song Chen ◽  
Wenjing Yao ◽  
Zihan Cheng ◽  
Boru Zhou ◽  
...  

Abstract Background The bZIP gene family, which is widely present in plants, participates in varied biological processes including growth and development and stress responses. How do the genes regulate such biological processes? Systems biology is powerful for mechanistic understanding of gene functions. However, such studies have not yet been reported in poplar. Results In this study, we identified 86 poplar bZIP transcription factors and described their conserved domains. According to the results of phylogenetic tree, we divided these members into 12 groups with specific gene structures and motif compositions. The corresponding genes that harbor a large number of segmental duplication events are unevenly distributed on the 17 poplar chromosomes. In addition, we further examined collinearity between these genes and the related genes from six other species. Evidence from transcriptomic data indicated that the bZIP genes in poplar displayed different expression patterns in roots, stems, and leaves. Furthermore, we identified 45 bZIP genes that respond to salt stress in the three tissues. We performed co-expression analysis on the representative genes, followed by gene set enrichment analysis. The results demonstrated that tissue differentially expressed genes, especially the co-expressing genes, are mainly involved in secondary metabolic and secondary metabolite biosynthetic processes. However, salt stress responsive genes and their co-expressing genes mainly participate in the regulation of metal ion transport, and methionine biosynthetic. Conclusions Using comparative genomics and systems biology approaches, we, for the first time, systematically explore the structures and functions of the bZIP gene family in poplar. It appears that the bZIP gene family plays significant roles in regulation of poplar development and growth and salt stress responses through differential gene networks or biological processes. These findings provide the foundation for genetic breeding by engineering target regulators and corresponding gene networks into poplar lines.


Author(s):  
Suhas Balasaheb Karle ◽  
Akankhya Guru ◽  
Padmanabh Dwivedi ◽  
Kundan Kumar
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