Class III peroxidases (PODs) are plant-specific glycoproteins, that play essential roles in various plant physiological processes and defence responses. To date, scarce information is available about the POD gene family in soybean. Hence, the present study is the first comprehensive report about the genome-wide characterization of GmPOD gene family in soybean (Glycine max L.). Here, we identified a total of 124 GmPOD genes in soybean, that are unevenly distributed across the genome. Phylogenetic analysis classified them into six distinct sub-groups (A-F), with one soybean specific subgroup. Exon-intron and motif analysis suggested the existence of structural and functional diversity among the sub-groups. Duplication analysis identified 58 paralogous gene pairs; segmental duplication and positive/Darwinian selection were observed as the major factors involved in the evolution of GmPODs. Furthermore, RNA-seq analysis revealed that 23 out of a total 124 GmPODs showed differential expression between drought-tolerant and drought-sensitive genotypes under stress conditions; however, two of them (GmPOD40 and GmPOD42) revealed the maximum deregulation in all contrasting genotypes. Overexpression (OE) lines of GsPOD40 showed considerably higher drought tolerance compared to wild type (WT) plants under stress treatment. Moreover, the OE lines showed enhanced photosynthesis and enzymatic antioxidant activities under drought stress, resulting in alleviation of ROS induced oxidative damage. Hence, the GsPOD40 enhanced drought tolerance in soybean by regulating the key physiological and biochemical pathways involved in the defence response. Lastly, the results of our study will greatly assist in further functional characterization of GsPODs in plant growth and stress tolerance in soybean.

Grasses represent a major family of monocots comprising mostly cereals. When compared to their eudicot counterparts, cereals show a remarkable morphological diversity. Understanding the molecular basis of floral organ identity and inflorescence development is crucial to gain insight into the grain development for yield improvement purposes in cereals, however, the exact genetic mechanism of floral organogenesis remains elusive due to their complex inflorescence architecture. Extensive molecular analyses of Arabidopsis and other plant genera and species have established the ABCDE floral organ identity model. According to this model, hierarchical combinatorial activities of A, B, C, D, and E classes of homeotic genes regulate the identity of different floral organs with partial conservation and partial diversification between eudicots and cereals. Here, we review the developmental role of A, B, C, D, and E gene classes and explore the recent advances in understanding the floral development and subsequent organ specification in major cereals with reference to model plants. Furthermore, we discuss the evolutionary relationships among known floral organ identity genes. This comparative overview of floral developmental genes and associated regulatory factors, within and between species, will provide a thorough understanding of underlying complex genetic and molecular control of flower development and floral organ identity, which can be helpful to devise innovative strategies for grain yield improvement in cereals.

Plant WRKY transcription factors (TFs) are active guardians against pathogens’ insurgency, key components in developmental processes, contributors in signal transduction pathways, and regulators of diverse biotic and abiotic stress responses. In this research, we isolated, cloned, and functionally characterized a new WRKY TF GmWRKY49 from soybean. GmWRKY49 is a nuclear protein which contains two highly conserved WRKY domains and a C₂H₂-type zinc-finger structure. The normalized expression (log₂ ratio) of GmWRKY49 was 2.75- and 1.90-fold in salt-tolerant and salt-susceptible soybean genotypes, respectively. The transcripts of GmWRKY49 could be detected in roots, stems, leaves, flowers, and almost no expression in pod tissues. The salinity-tolerance response of this gene was studied through overexpression in soybean composite seedlings and transgenic Arabidopsis. The effect of GmWRKY49 overexpression on root length of transgenic Arabidopsis was also investigated. Under salt stress, several parameters including germination rate, survival rate, root length, rosette diameter, relative electrolyte leakage, and proline content were significantly higher in composite seedlings and transgenic Arabidopsis than those in wild-type. Moreover, GmWRKY49 enhanced salinity tolerance in soybean mosaic seedlings and transgenic Arabidopsis. These results suggest that GmWRKY49 is a positive regulator of salinity tolerance in soybean and has high potential utilization for crop improvement.

MADS-box gene family members play multifarious roles in regulating the growth and development of crop plants and hold enormous promise for bolstering grain yield potential under changing global environments. Bread wheat (Triticum aestivum L.) is a key stable food crop around the globe. Until now, the available information concerning MADS-box genes in the wheat genome has been insufficient. Here, a comprehensive genome-wide analysis identified 300 high confidence MADS-box genes from the publicly available reference genome of wheat. Comparative phylogenetic analyses with Arabidopsis and rice MADS-box genes classified the wheat genes into 16 distinct subfamilies. Gene duplications were mainly identified in subfamilies containing unbalanced homeologs, pointing towards a potential mechanism for gene family expansion. Moreover, a more rapid evolution was inferred for M-type genes, as compared with MIKC-type genes, indicating their significance in understanding the evolutionary history of the wheat genome. We speculate that subfamily-specific distal telomeric duplications in unbalanced homeologs facilitate the rapid adaptation of wheat to changing environments. Furthermore, our in-silico expression data strongly proposed MADS-box genes as active guardians of plants against pathogen insurgency and harsh environmental conditions. In conclusion, we provide an entire complement of MADS-box genes identified in the wheat genome that could accelerate functional genomics efforts and possibly facilitate bridging gaps between genotype-to-phenotype relationships through fine-tuning of agronomically important traits.