Understanding the molecular basis of differential grain protein accumulation in wheat (Triticum aestivum L.) through expression profiling of transcription factors related to seed nutrients storage

Harnessing the potential of plant transcription factors in developing climate resilient crops to improve global food security: Current and future perspectives

Crop plants should be resilient to climatic factors in order to feed ever-increasing populations. Plants have developed stress-responsive mechanisms by changing their metabolic pathways and switching the stress-responsive genes. The discovery of plant transcriptional factors (TFs), as key regulators of different biotic and abiotic stresses, has opened up new horizons for plant scientists. TFs perceive the signal and switch certain stress-responsive genes on and off by binding to different cis-regulatory elements. More than 50 families of plant TFs have been reported in nature. Among them, DREB, bZIP, MYB, NAC, Zinc-finger, HSF, Dof, WRKY, and NF-Y are important with respect to biotic and abiotic stresses, but the potential of many TFs in the improvement of crops is untapped. In this review, we summarize the role of different stress-responsive TFs with respect to biotic and abiotic stresses. Further, challenges and future opportunities linked with TFs for developing climate-resilient crops are also elaborated.

High-Molecular-Weight Glutenin Subunits: Genetics, Structures, and Relation to End Use Qualities

High-molecular-weight glutenin subunits (HMW-GSs) are storage proteins present in the starchy endosperm cells of wheat grain. Encoding the synthesis of HMW-GS, the Glu-1 loci located on the long arms of group 1 chromosomes of the hexaploid wheat (1A, 1B, and 1D) present multiple allelism. In hexaploid wheat cultivars, almost all of them express 3 to 5 HMW-GSs and the 1Ay gene is always silent. Though HMW-GSs are the minor components in gluten, they are crucial for dough properties, and certain HMW-GSs make more positive contributions than others. The HMW-GS acts as a "chain extender" and provides a disulfide-bonded backbone in gluten network. Hydrogen bonds mediated by glutamine side chains are also crucial for stabilizing the gluten structure. In most cases, HMW-GSs with additional or less cysteines are related to the formation of relatively more or less interchain disulfide bonds and HMW-GSs also affect the gluten secondary structures, which in turn impact the end use qualities of dough.

Transcriptome wide identification and characterization of regulatory genes involved in EAA metabolism and validation through expression analysis in different developmental stages of finger millet spikes

Finger millet is a rich source of seed storage proteins (SSPs). Various regulatory genes play an important role to maintain the quality and accumulation of SSPs in crop seeds. In the present study, nine regulatory genes of EAAs metabolic pathway, i.e., aspartate kinase, homoserine dehydrogenase, threonine synthase, threonine dehydratase, dihydrodipicolinate synthase, cystathionine γ synthase, anthranilate synthase, acetolactate synthase and lysine 2-oxoglutarato reductase/saccharopine dehydrogenase (LOR/SD) were identified from the transcriptomic data of developing spikes of two finger millet genotypes, i.e., GP-45 and GP-1. Results of sequence alignment search and motif/domain analysis showed high similarity of nucleotide sequences of identified regulatory genes with their respective homologs in rice. Results of promoter analysis revealed the presence of various cis-regulatory elements, like nitrogen responsive cis-elements (O2-site and GCN4), light responsive cis-elements, and stress responsive cis-elements. The presence of nine regulatory genes identified from the transcriptomic data of GP-45 and GP-1 was further confirmed by real time expression analysis in high and low protein containing genotypes, i.e., GE-3885 and GE-1437. Results of real time expression analysis showed significantly higher expression (p ≤ 0.01) of regulatory genes in GE-3885 rather than GE-1437 under control and treatment condition. Crude protein content of GE-3885 was found to be significantly higher (p ≤ 0.01) in comparison to GE-1437 under control condition, while under treatment condition GE-1437 was found to be more responsive to KNO₃ treatment rather than GE-3885.