title: AtRAV1 and AtRAV2 overexpression in cotton increases fiber length differentially under drought stress and delays flowering.
abstract: There is a longstanding problem of an inverse relationship between cotton fiber qualities versus high yields. To better understand drought stress signaling and adaptation in cotton (Gossypium hirsutum) fiber development, we expressed the Arabidopsis transcription factors RELATED_TO_ABA-INSENSITIVE3/VIVIPAROUS1/(RAV1) and AtRAV2, which encode APETALA2-Basic3 domain proteins shown to repress transcription of FLOWERING_LOCUS_T (FT) and to promote stomatal opening cell-autonomously. In three years of field trials, we show that AtRAV1 and AtRAV2-overexpressing cotton had ∼5% significantly longer fibers with only marginal decreases in yields under well-watered or drought stress conditions that resulted in 40-60% yield penalties and 3-7% fiber length penalties in control plants. The longer transgenic fibers from drought-stressed transgenics could be spun into yarn which was measurably stronger and more uniform than that from well-watered control fibers. The transgenic AtRAV1 and AtRAV2 lines flowered later and retained bolls at higher nodes, which correlated with repression of endogenous GhFT-Like (FTL) transcript accumulation. Elevated expression early in development of ovules was observed for GhRAV2L, GhMYB25-Like (MYB25L) involved in fiber initiation, and GhMYB2 and GhMYB25 involved in fiber elongation. Altered expression of RAVs controlling critical nodes in developmental and environmental signaling hierarchies has the potential for phenotypic modification of crops.
authors.affiliation: Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, United States. Electronic address: amandeepamittal@gmail.com.
authors.forename: Amandeep
authors.initials: A
authors.lastname: Mittal
authors.affiliation: Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, United States. Electronic address: nevin.jiang@ttu.edu.
authors.forename: Yingwen
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Department of Plant and Soils Science, Texas Tech University, Lubbock, TX 79409-2122, United States. Electronic address: glen.ritchie@ttu.edu.
authors.forename: Glen L
authors.initials: GL
authors.lastname: Ritchie
authors.affiliation: USDA-ARS Plant Stress and Germplasm Laboratory, Lubbock, TX 79415, United States. Electronic address: jburke@lbk.ars.usda.gov.
authors.forename: John J
authors.initials: JJ
authors.lastname: Burke
authors.affiliation: Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, United States. Electronic address: chris.rock@ttu.edu.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Rock
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D032561:Cotton Fiber; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D055864:Droughts; D035264:Flowers / Q000235:genetics / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D003368:Gossypium / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013312:Stress, Physiological
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C117695:RAV1 protein, Arabidopsis; C117696:RAV2 protein, Arabidopsis
keywords: AtRAV; Fiber length; Florigen; Ovule development; Trichome