Soil salinity is one of the most limiting stresses for crop productivity and quality worldwide. In this sense, jasmonates (JAs) have emerged as phytohormones that play essential roles in mediating plant response to abiotic stresses, including salt stress. Here, we reviewed the mechanisms underlying the activation and response of the JA-biosynthesis and JA-signaling pathways under saline conditions in Arabidopsis and several crops. In this sense, molecular components of JA-signaling such as MYC2 transcription factor and JASMONATE ZIM-DOMAIN (JAZ) repressors are key players for the JA-associated response. Moreover, we review the antagonist and synergistic effects between JA and other hormones such as abscisic acid (ABA). From an applied point of view, several reports have shown that exogenous JA applications increase the antioxidant response in plants to alleviate salt stress. Finally, we discuss the latest advances in genomic techniques for the improvement of crop tolerance to salt stress with a focus on jasmonates.

Fungal diseases lead to significant losses in soybean yields and a decline in seed quality; such is the case of the Asian soybean rust and anthracnose caused by Phakopsora pachyrhizi and Colletotrichum truncatum, respectively. Currently, the development of transgenic plants carrying antifungal defensins offers an alternative for plant protection against pathogens. This paper shows the production of transgenic soybean plants expressing the NmDef02 defensin gene using the biolistic delivery system, in an attempt to improve resistance against diseases and reduce the need for chemicals. Transgenic lines were assessed in field conditions under the natural infections of P. pachyrhizi and C. truncatum. The constitutive expression of the NmDef02 gene in transgenic soybean plants was shown to enhance resistance against these important plant pathogens. The quantification of the P. pachyrhizi biomass in infected soybean leaves revealed significant differences between transgenic lines and the non-transgenic control. In certain transgenic lines there was a strong reduction of fungal biomass, revealing a less severe disease. Integration and expression of the transgenes were confirmed by PCR, Southern blot, and qRT-PCR, where the Def1 line showed a higher relative expression of defensin. It was also found that the expression of the NmDef02 defensin gene in plants of the Def1 line did not have a negative effect on the nodulation induced by Bradyrhizobium japonicum. These results indicate that transgenic soybean plants expressing the NmDef02 defensin gene have a substantially enhanced resistance to economically important diseases, providing a sound environmental approach for decreasing yield losses and lowering the burden of chemicals in agriculture.

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Plant defensins are a potential tool in crop improvement programs through biotechnology. Their antifungal action makes them attractive molecules for the production of transgenic plants. Information is currently lacking on what happens to the expression of defense genes in transgenic plants that overexpress a defensin. Here we show the relative expression of four defense-related genes: Mn-sod, PAL1, aos1 and HPL evaluated in two transgenic soybean events (Def1 and Def17) constitutively expressing the NmDef02 defensin gene. The expression of these defense genes showed a differential pro le in the transgenic events, with the increased expression of the aos1 gene and the repression of the Mn-sod gene in both events, when compared to the non-transgenic control. Furthermore, the expression of the PAL1 gene only increased in the Def17 event. The results indicate that the changes occurred in the expression of defense genes in transgenic plants overexpressing the defensin NmDef02; did not have a negative effect on morphoagronomic parameters when compared to the non-transgenic control.Understanding the molecular changes that occur in these transgenic plants could be of interest in the short, medium and long term.

Plant defensins are a potential tool in crop improvement programs through biotechnology. Their antifungal action makes them attractive molecules for the production of transgenic plants. Information is currently lacking on what happens to the expression of defense genes in transgenic plants that overexpress a defensin. Here we show the relative expression of four defense-related genes: Mn-sod, PAL1, aos1 and HPL evaluated in two transgenic soybean events (Def1 and Def17) constitutively expressing the NmDef02 defensin gene. The expression of these defense genes showed a differential profile in the transgenic events, with the increased expression of the aos1 gene and the repression of the Mn-sod gene in both events, when compared to the non-transgenic control. Furthermore, the expression of the PAL1 gene only increased in the Def17 event. The results indicate that the changes occurred in the expression of defense genes in transgenic plants overexpressing the defensin NmDef02; did not have a negative effect on morphoagronomic parameters when compared to the non-transgenic control. Understanding the molecular changes that occur in these transgenic plants could be of interest in the short, medium and long term.