Transcriptome Analysis of Arabidopsis GCR1 Mutant Reveals Its Roles in Stress, Hormones, Secondary Metabolism and Phosphate Starvation

Abstract

The controversy over the existence or the need for G-protein coupled receptors (GPCRs) in plant G-protein signalling has overshadowed a more fundamental quest for the role of AtGCR1, the most studied and often considered the best candidate for GPCR in plants. Our whole transcriptome microarray analysis of the GCR1-knock-out mutant (gcr1-5) in Arabidopsis thaliana revealed 350 differentially expressed genes spanning all chromosomes. Many of them were hitherto unknown in the context of GCR1 or G-protein signalling, such as in phosphate starvation, storage compound and fatty acid biosynthesis, cell fate, etc. We also found some GCR1-responsive genes/processes that are reported to be regulated by heterotrimeric G-proteins, such as biotic and abiotic stress, hormone response and secondary metabolism. Thus, GCR1 could have G-protein-mediated as well as independent roles and regardless of whether it works as a GPCR, further analysis of the organism-wide role of GCR1 has a significance of its own.

G-protein α-subunit (GPA1) regulates stress, nitrate and phosphate response, flavonoid biosynthesis, fruit/seed development and substantially shares GCR1 regulation in A. thaliana

“…It was found that gpa1-5 is similar to other known GPA1 mutants (Chen et al 2004 ;Jones et al 2003 ) with longer roots, fewer lateral roots, rounded leaves, reduced plant height, longer but fewer siliques, and smaller rosette ( Supplementary Fig. S1) as compared to the wild type, Ws2 (Chakraborty et al 2015 ). showing.…”

“…In addition, genome-wide interactome analysis of various G-protein subunits has been reported in Arabidopsis (Klopffleisch et al 2011 ). Functional genomics and in silico studies have also begun to answer the doubts regarding the role of GCR1 in plant heterotrimeric G-protein signalling (Chakraborty et al 2015 ;Taddese et al 2014 ). However, we neither know the complete GPA1mediated signaling pathway for the regulation of a single gene/process, nor the total number of genes/processes regulated by GPA1 on an organism-wide scale, let alone those shared by GCR1.…”

“…However, we neither know the complete GPA1mediated signaling pathway for the regulation of a single gene/process, nor the total number of genes/processes regulated by GPA1 on an organism-wide scale, let alone those shared by GCR1. This paper is an attempt to study the genomewide role of GPA1 by isolating its knock-out mutant and analysing its transcriptome, as well as comparing it with our similar analysis of the role of GCR1 (Chakraborty et al 2015 ), and with other transcriptome analyses on GPA1 (Booker et al 2012 ;Delgado-Cerezo et al 2012 ;Okamoto et al 2009 ;Pandey et al 2010 ).…”

Metabolite profiling and genome‐wide association studies reveal response mechanisms of phosphorus deficiency in maize seedling

“…As a result of the complexity of these adversity‐response mechanisms, however, many minor changes in expression and signaling confer distinct response phenotypes, such as different levels of low‐Pi sensitivity in maize inbred lines. Therefore, the number of related metabolites showing large‐amplitude differences between genotypes is relatively limited, unlike the dramatic variations between mutants and wild types (Chakraborty et al ., ; Pant et al ., ).…”

Proteínas G Heterotriméricas: Señalización De Plantas en Condiciones De Estrés Ambiental

“…Por otro lado, las proteínas MLO presentan un dominio 7TM, pero no se ha podido confirmar su acoplamiento con proteínas G (Urano y Jones, 2013). En apoyo a la hipótesis de que GCR1 es un GPCR en plantas, Chakraborty et al (2015b) realizaron un análisis del transcriptoma bajo las mismas condiciones para GPA1 y GCR1 en el cual compararon los genes de respuesta identificados para GPA1 y GCR1, en el que encontraron 104 genes en común, que corresponden a 26 y 30 % del total de los genes de respuesta identificados, respectivamente. Es decir, que GCR1 y GPA1 además de regular algunos genes en común, juegan un papel totalmente independiente entre sí.…”