Pyramiding of genes for grain protein content, grain quality, and rust resistance in eleven Indian bread wheat cultivars: a multi-institutional effort.

Improvement of grain protein content (GPC), loaf volume, and resistance to rusts was achieved in 11 Indian wheat cultivars that are widely grown in four different agro-climatic zones of India. This involved use of marker-assisted backcross breeding (MABB) for introgression and pyramiding of the following genes: (i) the high GPC gene Gpc-B1; (ii) HMW glutenin subunits 5 + 10 at Glu-D1 loci, and (iii) rust resistance genes, Yr36, Yr15, Lr24, and Sr24. GPC increased by 0.8 to 3.3%, although high GPC was generally associated with yield penalty. Further selection among high GPC lines allowed identification of progenies with higher GPC associated with improvement in 1000-grain weight and grain yield in the backgrounds of the following four cultivars: NI5439, UP2338, UP2382, and HUW468. The high GPC progenies (derived from NI5439) were also improved for grain quality using HMW glutenin subunits 5 + 10 at Glu-D1 loci. Similarly, progenies combining high GPC and rust resistance were obtained in the backgrounds of following five cultivars: Lok1, HD2967, PBW550, PBW621, and DBW1. The improved pre-bred lines developed following multi-institutional effort should prove a valuable source for the development of cultivars with improved nutritional quality and rust resistance in the ongoing wheat breeding programmes. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01277-w.

Overexpression of wheat transcription factor (TaHsfA6b) provides thermotolerance in barley.

MAIN CONCLUSION: Overexpressing a heat shock factor gene (TaHsfA6bT) from wheat provides thermotolerance in barley by constitutive expression of heat and other abiotic stress-response genes. Temperature is one of the most crucial abiotic factors defining the yield potential of temperate cereal crops, such as barley. The regulators of heat shock response (HSR), heat stress transcription factors (Hsfs), modulate the transcription level of heat-responsive genes to protect the plants from heat stress. In this study, an Hsf from wheat (TaHsfA6b) is overexpressed in barley for providing thermotolerance. Transgenic barley lines overexpressing TaHsfA6b showed improvement in thermotolerance. The constitutive overexpression of a TaHsfA6b gene upregulated the expression of major heat shock proteins and other abiotic stress-responsive genes. RNA-seq and qRT-PCR analysis confirmed the upregulation of Hsps, chaperonins, DNAJ, LEA protein genes, and genes related to anti-oxidative enzymes in transgenic lines. Excessive generation and accumulation of reactive oxygen species (ROS) occurred in wild-type (WT) plants during heat stress; however, the transgenic lines reflected improved ROS homeostasis mechanisms, showing lesser ROS accumulation under high temperature. No negative phenotypic changes were observed in overexpression lines. These results suggest that TaHsfA6b is a regulator of HSR and its overexpression altered the expression patterns of some main stress-related genes and enhanced the thermotolerance of this cereal crop.

Updated inventory, evolutionary and expression analyses of G (PDR) type ABC transporter genes of rice.

ABC transporters constitute the largest family of transporter proteins in living organisms and divided into eight subfamilies, from A-H. ABCG members, specific to plants and fungi, belong to subfamily G. In this study, we provide updated inventory, detailed account of phylogeny, gene structure characteristics, and expression profiling during reproductive development, abiotic and biotic stresses of members of ABCG gene family in rice along with reannotation and cloning of FL-cDNA of OsABCG50/PDR23. We observed that of the 22 ABCGs/PDRs, four genes evolved as a result of gene duplication events and their expression pattern changed after duplication. Analysis of expression revealed seed and developmental stage preferential expression of five ABCG/PDR members. Transcript levels of eight ABCGs/PDRs were affected by abiotic and biotic stresses. Expression of seven ABCG/PDR genes was also altered by hormonal elicitors. The modulated expression is nicely correlated with the presence of tissue/stress specific cis-acting elements present in putative promoter region.

Genome-wide identification and expression analysis of Hsp70, Hsp90, and Hsp100 heat shock protein genes in barley under stress conditions and reproductive development.

Abiotic stress including extreme temperature disturbs the plant cellular homeostasis consequently limiting the yield potential of crop plants. Heat shock proteins (Hsps) are part of major rescue machinery of plants which aid to combat these stressed conditions by re-establishing protein homeostasis. Hsps with their chaperone and co-chaperone mechanisms regulate the activity of their substrate proteins in an ATP-dependent manner. In the present investigation, a genome-wide identification, evolutionary relationship, and comprehensive expression analysis of Hsp70, Hsp90, and Hsp100 gene families have been done in barley. The barley genome possesses 13 members of the Hsp70 gene family, along with 4 members of the Hsp110 subfamily, and 6 members of Hsp90 and 8 members of the Hsp100 gene family. Hsp genes are distributed on all 7 chromosomes of barley, and their encoded protein members are predicted to be localized to cell organelles such as cytosol, mitochondria, chloroplast, and ER. Despite a larger genome size, there are lesser members of these Hsp genes in barley, owing to less duplication events. The variable expression pattern obtained for genes encoding proteins localized to the same subcellular compartment suggests their diverse roles and involvement in different cellular responses. Expression profiling of these genes was performed by qRT-PCR in an array of 32 tissues, which showed a differential and tissue-specific expression of various members of Hsp gene families. We found the upregulation of HvHspc70-4, HvHsp70Mt70-2, HvHspc70-5a, HvHspc70-5b, HvHspc70-N1, HvHspc70-N2, HvHsp110-3, HvHsp90-1, HvHsp100-1, and HvHsp100-2 upon exposure to heat stress during reproductive development. Furthermore, their higher expression during heat stress, heavy metal stress, drought, and salinity stress was also observed in a tissue-specific manner.