title: Genome-wide analysis of the GH3 family in apple (Malus × domestica).
abstract: BACKGROUND
  Auxin plays important roles in hormone crosstalk and the plant's stress response. The auxin-responsive Gretchen Hagen3 (GH3) gene family maintains hormonal homeostasis by conjugating excess indole-3-acetic acid (IAA), salicylic acid (SA), and jasmonic acids (JAs) to amino acids during hormone- and stress-related signaling pathways. With the sequencing of the apple (Malus × domestica) genome completed, it is possible to carry out genomic studies on GH3 genes to indentify candidates with roles in abiotic/biotic stress responses.
  
  
  RESULTS
  Malus sieversii Roem., an apple rootstock with strong drought tolerance and the ancestral species of cultivated apple species, was used as the experimental material. Following genome-wide computational and experimental identification of MdGH3 genes, we showed that MdGH3s were differentially expressed in the leaves and roots of M. sieversii and that some of these genes were significantly induced after various phytohormone and abiotic stress treatments. Given the role of GH3 in the negative feedback regulation of free IAA concentration, we examined whether phytohormones and abiotic stresses could alter the endogenous auxin level. By analyzing the GUS activity of DR5::GUS-transformed Arabidopsis seedlings, we showed that ABA, SA, salt, and cold treatments suppressed the auxin response. These findings suggest that other phytohormones and abiotic stress factors might alter endogenous auxin levels.
  
  
  CONCLUSIONS
  Previous studies showed that GH3 genes regulate hormonal homeostasis. Our study indicated that some GH3 genes were significantly induced in M. sieversii after various phytohormone and abiotic stress treatments, and that ABA, SA, salt, and cold treatments reduce the endogenous level of axuin. Taken together, this study provides evidence that GH3 genes play important roles in the crosstalk between auxin, other phytohormones, and the abiotic stress response by maintaining auxin homeostasis.
authors: Department of Fruit Science, College of Agriculture and Biotechnology/Key Laboratory of Stress Physiology and Molecular Biology for Tree Fruits of Beijing, China Agricultural University, 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China.
authors: Huazhao
authors: H
authors: Yuan
authors: Kai
authors: K
authors: Zhao
authors: Hengjiu
authors: H
authors: Lei
authors: Xinjie
authors: X
authors: Shen
authors: Yun
authors: Y
authors: Liu
authors: Xiong
authors: X
authors: Liao
authors: Tianhong
authors: T
authors: Li
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018745:Genome, Plant / Q000235:genetics; D055106:Genome-Wide Association Study; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology; D027845:Malus / Q000235:genetics* / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000235:genetics; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D030821:Plants, Genetically Modified; D020156:Salicylic Acid / Q000378:metabolism; D013312:Stress, Physiological / Q000502:physiology
chemical_list: D003517:Cyclopentanes; D007210:Indoleacetic Acids; D054883:Oxylipins; D010937:Plant Growth Regulators; C011006:jasmonic acid; C030737:indoleacetic acid; D005966:Glucuronidase; D020156:Salicylic Acid
references: FEBS J. 2010 Jul;277(14):2954-69
references: 20528920
references: Annu Rev Genet. 2009;43:265-85
references: 19686081
references: Plant Cell. 1995 Oct;7(10):1611-23
references: 7580254
references: Cell. 1999 Nov 24;99(5):463-72
references: 10589675
references: Funct Integr Genomics. 2010 Nov;10(4):533-46
references: 20499123
references: Nucleic Acids Res. 2003 Jan 1;31(1):68-71
references: 12519949
references: Plant Physiol. 2004 Sep;136(1):2621-32
references: 15375207
references: EMBO J. 1987 Dec 20;6(13):3901-7
references: 3327686
references: Plant Cell. 2002 Jun;14(6):1405-15
references: 12084835
references: Plant Cell. 2008 Jan;20(1):228-40
references: 18192436
references: Trends Genet. 2000 Oct;16(10):449-55
references: 11050331
references: Plant Cell. 1997 Nov;9(11):1963-71
references: 9401121
references: Plant Cell Physiol. 2002 Mar;43(3):281-9
references: 11917082
references: Plant Physiol. 2009 Sep;151(1):275-89
references: 19625633
references: Mol Plant Microbe Interact. 2009 Feb;22(2):201-10
references: 19132872
references: Plant Cell. 2004 Aug;16(8):2117-27
references: 15258265
references: Plant Cell Environ. 2008 Jun;31(6):783-92
references: 18266905
references: Gene. 2006 Apr 26;371(2):279-90
references: 16488558
references: Plant Cell. 1998 Oct;10(10):1649-62
references: 9761792
references: Nucleic Acids Res. 2002 Jan 1;30(1):207-10
references: 11752295
references: Plant Cell. 1994 May;6(5):645-57
references: 8038604
references: Plant Cell. 2001 Apr;13(4):843-52
references: 11283340
references: BMC Plant Biol. 2012 Jan 13;12:7
references: 22243694
references: Plant Physiol. 2004 Oct;136(2):2982-3000
references: 15466221
references: Yi Chuan. 2007 Aug;29(8):1023-6
references: 17681935
references: Genome Res. 2006 Sep;16(9):1159-68
references: 16951135
references: Mol Biol Evol. 2011 Oct;28(10):2731-9
references: 21546353
references: Plant J. 2005 Jul;43(1):29-46
references: 15960614
references: Genome Res. 2009 Sep;19(9):1639-45
references: 19541911
references: Plant J. 2004 Feb;37(4):471-83
references: 14756757
references: Curr Biol. 2007 Oct 23;17(20):1784-90
references: 17919906
references: Plant Mol Biol. 2002 Jun-Jul;49(3-4):373-85
references: 12036261
references: Plant Physiol. 2009 Dec;151(4):1889-901
references: 19776160
references: Nat Genet. 2010 Oct;42(10):833-9
references: 20802477
references: Bioinformatics. 2003 Aug 12;19(12):1585-6
references: 12912844
references: J Genet Genomics. 2007 Feb;34(2):171-9
references: 17469789
references: Curr Opin Plant Biol. 2000 Aug;3(4):309-14
references: 10873851
references: Bioinformatics. 1998;14(9):755-63
references: 9918945
references: Plant Physiol. 2006 Oct;142(2):553-63
references: 16905669
references: Plant Cell. 2005 Feb;17(2):616-27
references: 15659623
references: J Biol Chem. 2007 Mar 30;282(13):10036-10046
references: 17276977
references: Funct Integr Genomics. 2006 Jan;6(1):36-46
references: 15856348
references: Methods. 2001 Dec;25(4):402-8
references: 11846609
references: Plant Cell Physiol. 2007 Aug;48(8):1236-41
references: 17602188
references: Science. 1997 Jun 20;276(5320):1865-8
references: 9188533
references: J Exp Bot. 2010 Aug;61(13):3615-25
references: 20581124
references: Science. 2006 Apr 21;312(5772):436-9
references: 16627744
references: FEBS J. 2009 Jun;276(11):3148-62
references: 19490115
references: Mol Cell Biol. 1985 Jun;5(6):1197-203
references: 4041007