title: Overexpression of Arabidopsis YUCCA6 in potato results in high-auxin developmental phenotypes and enhanced resistance to water deficit.
abstract: Indole-3-acetic acid (IAA), a major plant auxin, is produced in both tryptophan-dependent and tryptophan-independent pathways. A major pathway in Arabidopsis thaliana generates IAA in two reactions from tryptophan. Step one converts tryptophan to indole-3-pyruvic acid (IPA) by tryptophan aminotransferases followed by a rate-limiting step converting IPA to IAA catalyzed by YUCCA proteins. We identified eight putative StYUC (Solanum tuberosum YUCCA) genes whose deduced amino acid sequences share 50%-70% identity with those of Arabidopsis YUCCA proteins. All include canonical, conserved YUCCA sequences: FATGY motif, FMO signature sequence, and FAD-binding and NADP-binding sequences. In addition, five genes were found with ~50% amino acid sequence identity to Arabidopsis tryptophan aminotransferases. Transgenic potato (Solanum tuberosum cv. Jowon) constitutively overexpressing Arabidopsis AtYUC6 displayed high-auxin phenotypes such as narrow downward-curled leaves, increased height, erect stature, and longevity. Transgenic potato plants overexpressing AtYUC6 showed enhanced drought tolerance based on reduced water loss. The phenotype was correlated with reduced levels of reactive oxygen species in leaves. The results suggest a functional YUCCA pathway of auxin biosynthesis in potato that may be exploited to alter plant responses to the environment.
authors.affiliation: Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Jeong Im
authors.initials: JI
authors.lastname: Kim
authors.forename: Dongwon
authors.initials: D
authors.lastname: Baek
authors.forename: Hyeong Cheol
authors.initials: HC
authors.lastname: Park
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Chun
authors.forename: Dong-Ha
authors.initials: DH
authors.lastname: Oh
authors.forename: Min Kyung
authors.initials: MK
authors.lastname: Lee
authors.forename: Joon-Yung
authors.initials: JY
authors.lastname: Cha
authors.forename: Woe-Yeon
authors.initials: WY
authors.lastname: Kim
authors.forename: Min Chul
authors.initials: MC
authors.lastname: Kim
authors.forename: Woo Sik
authors.initials: WS
authors.lastname: Chung
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Bohnert
authors.forename: Sang Yeol
authors.initials: SY
authors.lastname: Lee
authors.forename: Ray A
authors.initials: RA
authors.lastname: Bressan
authors.forename: Shin-Woo
authors.initials: SW
authors.lastname: Lee
authors.forename: Dae-Jin
authors.initials: DJ
authors.lastname: Yun
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics*; D030541:Databases, Genetic; D015870:Gene Expression; D007210:Indoleacetic Acids / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010641:Phenotype; D011198:Solanum tuberosum / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D013312:Stress, Physiological; D051279:Tryptophan Transaminase / Q000235:genetics; D014867:Water / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D014867:Water; C030737:indoleacetic acid; D006899:Mixed Function Oxygenases; C562183:YUCCA6 protein, Arabidopsis; D051279:Tryptophan Transaminase