The Role of Tomato WRKY Genes in Plant Responses to Combined Abiotic and Biotic Stresses

Abstract

In the field, plants constantly face a plethora of abiotic and biotic stresses that can impart detrimental effects on plants. In response to multiple stresses, plants can rapidly reprogram their transcriptome through a tightly regulated and highly dynamic regulatory network where WRKY transcription factors can act as activators or repressors. WRKY transcription factors have diverse biological functions in plants, but most notably are key players in plant responses to biotic and abiotic stresses. In tomato there are 83 WRKY genes identified. Here we review recent progress on functions of these tomato WRKY genes and their homologs in other plant species, such as Arabidopsis and rice, with a special focus on their involvement in responses to abiotic and biotic stresses. In particular, we highlight WRKY genes that play a role in plant responses to a combination of abiotic and biotic stresses.

Keywords: PAMP-triggered immunity (PTI); abiotic stress; biotic stress; combined stresses; disease resistance; effector-triggered immunity (ETI).

FIGURE 1

The involvements of Group I and III tomato SlWRKY genes and their homologs (highlighted in different colors) in plant responses to biotic and abiotic stresses. The phylogenetic relations of tomato SlWRKYs and their homologs in Arabidopsis (AtWRKYs), rice (OsWRKYs), tobacco (NtWRKY), wheat (TaWRKY), barley (HvWRKY), cotton (GhWRKY), and grape (VqWKRY) are based on the phylogenetic tree presented in Supplementary Figure S1.

FIGURE 2

The involvements of the Group II tomato SlWRKY genes and their homologs (highlighted in different colors) in plant responses to biotic and abiotic stresses. The phylogenetic relations of tomato SlWRKYs and their homologs in Arabidopsis (AtWRKYs), rice (OsWRKYs), wheat (TaWRKY), and barley (HvWRKY) are based on the phylogenetic tree presented in Supplementary Figure S1.