Genetic analysis of Arabidopsis GATA transcription factor gene family reveals a nitrae-inducible member important for chlorophyll synthesis and glucose sensitivity

Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
The Plant Journal (Impact Factor: 5.97). 12/2005; 44(4):680-92. DOI: 10.1111/j.1365-313X.2005.02568.x
Source: PubMed


The Arabidopsis GATA transcription factor family has 30 members, the biological function of most of which is poorly understood. Homozygous T-DNA insertion lines for 23 of the 30 members were identified and analyzed. Genetic screening of the insertion lines in defined growth conditions revealed one line with an altered phenotype, while the other lines showed no obvious change. This line, SALK_001778, has a T-DNA insertion in the second exon of At5g56860 which prevents the expression of the GATA domain. Genetic analysis of the mutant demonstrated that the phenotypic change is caused by a single gene effect and is recessive to the wild-type allele. In wild-type plants, the expression of At5g56860 is shoot-specific, occurs at an early stage of development and is inducible by nitrate. Loss of expression of At5g56860 in the loss-of-function mutant plants resulted in reduced chlorophyll levels. A transcript profiling experiment revealed that a considerable proportion of genes downregulated in the loss-of-function mutants are involved in carbon metabolism and At5g56860 is thus designated GNC (GATA, nitrate-inducible, carbon metabolism-involved). gnc mutants with no GNC expression are more sensitive to exogenous glucose, and two hexose transporter genes, with a possible connection to glucose signaling, are significantly downregulated, while GNC over-expressing transgenic plants upregulate their expression and are less sensitive to exogenous glucose. These observations suggest a function for GNC in regulating carbon and nitrogen metabolism.

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Available from: Yong-Mei Bi, Nov 20, 2014
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    • "A second example from the Rothstein laboratory is based on work initiated in 2002. This work involved analysing GATA transcription factor mutants in Arabidopsis and the identification of one that we called GNC (for GATA-nitrate regulatedcarbon metabolism involved; Bi et al., 2005; reviewed in Kant et al., 2011). GNC and a paralogue gene called CGA-1 both modulate the level of chlorophyll and chloroplast number, particularly under nitrogen limitation conditions (Hudson et al., 2011). "
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    • "CGA1 was regulated by light, nitrogen, cytokinin, and gibberellic acid, and modulated nitrogen assimilation, chloroplast development, and starch production (Bi et al., 2005; Naito et al., 2007; Mara and Irish, 2008; Richter et al., 2010; Hudson et al., 2011); CGA1 play a key role in chloroplast development, growth, and divison in Arabidopsis (Chiang et al., 2012) AP2-EREBP At4g34410 RRTF1 (redox-responsive transcription factor 1) RTF1 is involved in redox homeostasis under high light stress (Khandelwal et al., 2008) AP2-EREBP At5g05410 DREB2A (dehydration-responsive element-binding protein 2A) DREB2A is involved in dehydrationresponsive gene expression and overexpression of an active form of DREB2A results in significant stress tolerance to dehydration and significant growth retardation (Sakuma et al., 2006) C2H2 At5g59820 ZAT12 Zat12 plays a central role in reactive oxygen and abiotic stress signalling in Arabidopsis and overexpression of Zat12 in Arabidopsis results in the enhanced expression of oxidative-and light stress-response transcripts (Davletova et al., 2005) Downregulated under low CO 2 C2C2-CO-like At1g49130 COL8 (CONSTANS-LIKE 8) Zinc finger (B-box type) family protein SBP At2g33810 SPL3 (SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 3) SPL3 is involved in regulation of flowering and vegetative phase change (Cardon et al., 1997; Wu and Poethig, 2006; Yamaguchi et al., 2009) C2C2-CO-like At4g27310 BBX28 Zinc finger (B-box type) family protein G2-like At5g44190 GLK2 (Golden2-like 2) GLK2 is required for normal chloroplast development (Fitter et al., 2002); GLK2 together with GLK1 optimize photosynthetic capacity by integrating responses to variable enironmental and endogenous cues (Waters et al., 2009) MADS At5g62165 AGL42 (AGAMOUS-LIKE 42) AGL42 is involved in the floral transition and RNAi-directed downregulation of AGL24 results in late flowering (Yu et al., 2002) a mechanism to allow for greater accumulation of stored reserves that could be allocated to reproduction, resulting in increased fitness under low CO 2 (Sage and Coleman, 2001; Ward, 2005). Many studies have shown that atmospheric CO 2 concentration negatively regulates stomatal density (Woodward, 1987; Beerling et al., 2001; Franks and Beerling, 2009; Doheny- Adams et al., 2012; Franks et al., 2012). "
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