title: Tomato SR/CAMTA transcription factors SlSR1 and SlSR3L negatively regulate disease resistance response and SlSR1L positively modulates drought stress tolerance.
abstract: BACKGROUND
  The SR/CAMTA proteins represent a small family of transcription activators that play important roles in plant responses to biotic and abiotic stresses. Seven SlSR/CAMTA genes were identified in tomato as tomato counterparts of SR/CAMTA; however, the involvement of SlSRs/CAMTAs in biotic and abiotic stress responses is not clear. In this study, we performed functional analysis of the SlSR/CAMTA family for their possible functions in defense response against pathogens and tolerance to drought stress.
  
  
  RESULTS
  Expression of SlSRs was induced with distinct patterns by Botrytis cinerea and Pseudomonas syringae pv. tomato (Pst) DC3000. Virus-induced gene silencing (VIGS)-based knockdown of either SlSR1 or SlSR3L in tomato resulted in enhanced resistance to B. cinerea and Pst DC3000 and led to constitutive accumulation of H2O2, elevated expression of defense genes, marker genes for pathogen-associated molecular pattern-triggered immunity, and regulatory genes involved in the salicylic acid- and ethylene-mediated signaling pathways. Furthermore, the expression of SlSR1L and SlSR2L in detached leaves and whole plants was significantly induced by drought stress. Silencing of SlSR1L led to decreased drought stress tolerance, accelerated water loss in leaves, reduced root biomass and attenuated expression of drought stress responsive genes in tomato. The SlSR1 and SlSR3L proteins were localized in the nucleus of plant cells when transiently expressed in Nicotiana benthamiana and had transcriptional activation activity in yeast.
  
  
  CONCLUSIONS
  VIGS-based functional analyses demonstrate that both SlSR1 and SlSR3L in the tomato SlSR/CAMTA family are negative regulators of defense response against B. cinerea and Pst DC3000 while SlSR1L is a positive regulator of drought stress tolerance in tomato.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.forename: Yafen
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Ouyang
authors.forename: Yongbo
authors.initials: Y
authors.lastname: Hong
authors.forename: Huijuan
authors.initials: H
authors.lastname: Zhang
authors.forename: Dayong
authors.initials: D
authors.lastname: Li
authors.forename: Fengming
authors.initials: F
authors.lastname: Song
mesh_terms: D020171:Botrytis / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism; D060467:Disease Resistance; D055864:Droughts; D005030:Ethylenes / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D010935:Plant Diseases / Q000276:immunology*; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000276:immunology / Q000502:physiology; D044224:Pseudomonas syringae / Q000502:physiology*; D020156:Salicylic Acid / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D005030:Ethylenes; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors; C036216:ethylene; D006861:Hydrogen Peroxide; D020156:Salicylic Acid