Tomato NAC Transcription Factor SlSRN1 Positively Regulates Defense Response against Biotic Stress but Negatively Regulates Abiotic Stress Response

Abstract

Biotic and abiotic stresses are major unfavorable factors that affect crop productivity worldwide. NAC proteins comprise a large family of transcription factors that play important roles in plant growth and development as well as in responses to biotic and abiotic stresses. In a virus-induced gene silencing-based screening to identify genes that are involved in defense response against Botrytis cinerea, we identified a tomato NAC gene SlSRN1 (Solanum lycopersicum Stress-related NAC1). SlSRN1 is a plasma membrane-localized protein with transactivation activity in yeast. Expression of SlSRN1 was significantly induced by infection with B. cinerea or Pseudomonas syringae pv. tomato (Pst) DC3000, leading to 6–8 folds higher than that in the mock-inoculated plants. Expression of SlSRN1 was also induced by salicylic acid, jasmonic acid and 1-amino cyclopropane-1-carboxylic acid and by drought stress. Silencing of SlSRN1 resulted in increased severity of diseases caused by B. cinerea and Pst DC3000. However, silencing of SlSRN1 resulted in increased tolerance against oxidative and drought stresses. Furthermore, silencing of SlSRN1 accelerated accumulation of reactive oxygen species but attenuated expression of defense genes after infection by B. cinerea. Our results demonstrate that SlSRN1 is a positive regulator of defense response against B. cinerea and Pst DC3000 but is a negative regulator for oxidative and drought stress response in tomato.

Tomato SlERF.A1, SlERF.B4, SlERF.C3 and SlERF.A3, Members of B3 Group of ERF Family, Are Required for Resistance to Botrytis cinerea

“…The significant accumulation of H 2 O 2 in leaves of the SlERF.A1 -, SlERF.A3 -, SlERF.B4 -, and SlERF.C3 -silenced plants after infection of B. cinerea ( Figure 7 ) may suggest that the function of SlERF.A1, SlERF.A3, SlERF.B4, and SlERF.C3 in defense response against B. cinerea links to ROS generation. Similar correlation of enhanced ROS accumulation and increased B. cinerea susceptibility were also observed in SlSRN1 -, SlMKK2 -, or SlMKK4 -silenced tomato plants (Li et al, 2014b; Liu et al, 2014b). …”

“…It was shown that ABA regulates the immunity to B. cinerea in tomato through modulating the cuticle permeability and pectin composition in cell wall or suppressing the SA-mediated signaling pathway or the production of nitric oxide (Audenaert et al, 2002; Asselbergh et al, 2007; Curvers et al, 2010; Sivakumaran et al, 2016). A number of genes encoding receptor-like protein kinase TPK1b, transcriptional factors SHINE3, AIM1, SlDRW1, SlSRN1, SlSR1, and SlSR3L (Abuqamar et al, 2008, 2009; Buxdorf et al, 2014; Li et al, 2014a; Liu et al, 2014a,b), histone H2B monoubiquitination enzymes SlHUB1 and SlHUB2 (Zhang Y. et al, 2015), mitogen-activated protein kinase kinase SlMKK2 and SlMKK4 (Li et al, 2014b), phosphatidylinositol-phospholipase SlPLC2 (Gonorazky et al, 2016), NADPH oxidase SlRbohB (Li X. et al, 2015), 12-oxophytodienoate reductase SlOPR3 (Scalschi et al, 2015) and matrix metalloproteinase Sl3-MMP (Li D. et al, 2015) have been identified to play important roles in tomato immunity against B. cinerea . Enzymes involved in biosynthesis of vitamin B6 and trehalose-6-phosphate as well as concurrent over-activation of cytosolic glutamine synthetase and γ-aminobutyric acid shunt are also involved in tomato immune response to B. cinerea (Seifi et al, 2013; Zhang et al, 2014, 2016).…”

Sugarcane transcriptome analysis in response to infection caused by Acidovorax avenae subsp. avenae

“…Out of the 467 differentially expressed genes, six were exclusively expressed in infected plants and only 1 in control plants (aldehyde dehydrogenase putative protein) (Table 5). NAC proteins are involved in developmental processes [59,60], hormone signaling [61,62], secondary cell-wall synthesis and programmed cell death [63,64] and in plant responses to abiotic and biotic stresses [65–67]. The amino acid transporters are membrane proteins that mediate the flow of amino acids in plants and have various roles in the growth and development of plants, including metabolism of nucleotides, chlorophyll, hormones and secondary metabolites [68,69].…”

Characterization, Expression, and Functional Analysis of a Novel NAC Gene Associated with Resistance to Verticillium Wilt and Abiotic Stress in Cotton

“…SISRN1 , a tomato NAC gene, was involved in the response to Botrytis cinerea (Liu et al 2014a). NTP1 and NTP2 , two NAC proteins from potato and N. benthamiana , are involved in the response to P. infestans (McLellan et al 2013).…”