Differential Regulation of Genes Coding for Organelle and Cytosolic ClpATPases under Biotic and Abiotic Stresses in Wheat

Abstract

A sub-group of class I Caseinolytic proteases (Clps) function as molecular chaperone and confer thermotolerance to plants. We identified class I Clp family consisting of five ClpB/HSP100, two ClpC, and two ClpD genes from bread wheat. Phylogenetic analysis showed that these genes were highly conserved across grass genomes. Subcellular localization prediction revealed that TaClpC and TaClpD subgroup proteins and TaClpB1 proteins are potentially targeted to chloroplast, while TaClpB5 to mitochondria, and TaClpB2, TaClpB3, and TaClpB4 to cytoplasm. Spatio-temporal expression pattern analysis revealed that four TaClpB and TaClpD2 genes are expressed in majority of all tissues and developmental stages of wheat. Real-time RT-PCR analysis of expression levels of Clp genes in seven wheat genotypes under different abiotic stresses revealed that genes coding for the cytosolic Clps namely TaClpB2 and TaClpB3 were upregulated under heat, salt and oxidative stress but were downregulated by cold stress in most genotypes. In contrast, genes coding for the chloroplastic Clps TaClpC1, TaClpC2, and TaClpD1 genes were significantly upregulated by mainly by cold stress in most genotypes, while TaClpD2 gene was upregulated >2 fold by salt stress in DBW16. The TaClpB5 gene coding for mitochondrial Clp was upregulated in all genotypes under heat, salt and oxidative stresses. In addition, we found that biotic stresses also upregulated TaClpB4 and TaClpD1. Among biotic stresses, Tilletia caries induced TaClpB2, TaClpB3, TaClpC1, and TaClpD1. Differential expression pattern under different abiotic and biotic stresses and predicted differential cellular localization of Clps suggest their non-redundant organelle and stress-specific roles. Our results also suggest the potential role of Clps in cold, salt and biotic stress responses in addition to the previously established role in thermotolerance of wheat.

Genome-wide analysis of the HSP101/CLPB gene family for heat tolerance in hexaploid wheat

“…The other two genes of wheat HSP101 were cloned later and named as TaHSP101B and TaHSP101C, while the first HSP101 was renamed as TaHSP101A 37 . An in-silico study of the Caseinolytic Protease Class I family has predicted five members of the CLPB family in wheat: three of them are cytoplasmic copies and one copy each of the other two is targeted to the chloroplast and mitochondria 38 . These genes were shown to be differentially expressed at different tissues and stress conditions 37,38 .…”

“…An in-silico study of the Caseinolytic Protease Class I family has predicted five members of the CLPB family in wheat: three of them are cytoplasmic copies and one copy each of the other two is targeted to the chloroplast and mitochondria 38 . These genes were shown to be differentially expressed at different tissues and stress conditions 37,38 . Cytoplasmic CLPBs were up-regulated in leaves under heat, salt and oxidative stress 38 .…”

Identification of watermelon heat shock protein members and tissue-specific gene expression analysis under combined drought and heat stresses

“…Complete genomic data of organisms are useful for determining important gene families using bioinformatics methods. Hsps have been characterized in many plant species, including Arabidopsis (Swindell et al, 2007), wheat (Muthusamy et al, 2017), sunflower , rice (Singh et al, 2010;Jiang et al, 2014;Wang et al, 2014), tomato (Zai et al, 2017), poplar (Yer et al, 2016;Yer et al, 2018), and eucalyptus (Altunoğlu, 2016). The complete genome sequence of watermelon was published by Guo et al in 2013; however, to our knowledge, Hsp family members have not yet been defined in the watermelon genome.…”

Development and validation of microsatellite markers for Karnal bunt (Tilletia indica) and loose smut (Ustilago segetum tritici) of wheat from related fungal species

“…Minimum efforts have been made to understand the genetic and molecular diversity of the T. indica pathogen. The availability of the whole genome sequence of fungal pathogens is of great utility which allows researchers to discover resistance genes, regulatory sequences, virulence genes and molecular markers (Aylward et al, 2017;Muthusamy, Dalal, Chinnusamy, & Bansal, 2016). Genome-based SSRs have proven to be useful markers for genetic characterization of fungal species (Kaye, Milazzo, Rozenfeld, Lebrun, & Tharreau, 2003;Singh et al, 2011).…”