Plant metabolomics is a rapidly advancing field of plant sciences and systems biology. It involves comprehensive analyses of small molecules (metabolites) in plant tissues and cells. These metabolites include a wide range of compounds, such as sugars, amino acids, organic acids, secondary metabolites (e.g., alkaloids and flavonoids), lipids, and more. Metabolomics allows an understanding of the functional roles of specific metabolites in plants’ physiology, development, and responses to biotic and abiotic stresses. It can lead to the identification of metabolites linked with specific traits or functions. Plant metabolic networks and pathways can be better understood with the help of metabolomics. Researchers can determine how plants react to environmental cues or genetic modifications by examining how metabolite profiles change under various crop stages. Metabolomics plays a major role in crop improvement and biotechnology. Integrating metabolomics data with other omics data (genomics, transcriptomics, and proteomics) provides a more comprehensive perspective of plant biology. This systems biology approach enables researchers to understand the complex interactions within organisms.

Stomata regulates conductance, transpiration and photosynthetic traits in plants. Increased stomatal density may contribute to enhanced water loss and thereby help improve the transpirational cooling process and mitigate the high temperature-induced yield losses. However, genetic manipulation of stomatal traits through conventional breeding still remains a challenge due to problems involved in phenotyping and the lack of suitable genetic materials. Recent advances in functional genomics in rice identified major effect genes determining stomatal traits, including its number and size. Widespread applications of CRISPR/Cas9 in creating targeted mutations paved the way for fine tuning the stomatal traits for enhancing climate resilience in crops. In the current study, attempts were made to create novel alleles of OsEPF1 (Epidermal Patterning Factor), a negative regulator of stomatal frequency/density in a popular rice variety, ASD 16, using the CRISPR/Cas9 approach. Evaluation of 17 T₀ progenies identified varying mutations (seven multiallelic, seven biallelic and three monoallelic mutations). T₀ mutant lines showed a 3.7–44.3% increase in the stomatal density, and all the mutations were successfully inherited into the T₁ generation. Evaluation of T₁ progenies through sequencing identified three homozygous mutants for one bp insertion. Overall, T₁ plants showed 54–95% increased stomatal density. The homozygous T₁ lines (# E1-1-4, # E1-1-9 and # E1-1-11) showed significant increase in the stomatal conductance (60–65%), photosynthetic rate (14–31%) and the transpiration rate (58–62%) compared to the nontransgenic ASD 16. Results demonstrated that the genetic alterations in OsEPF1 altered the stomatal density, stomatal conductance and photosynthetic efficiency in rice. Further experiments are needed to associate this technology with canopy cooling and high temperature tolerance.

Across the globe, rice cultivation is seriously affected by blast disease, caused by Magnaporthe oryzae. This disease has caused heavy yield loss to farmers over the past few years. In this background, the most affordable and eco-friendly strategy is to introgress blast-resistant genes from donors into elite rice cultivars. However, it is not only challenging to evolve such resistance lines using conventional breeding approaches, but also a time-consuming process. Therefore, the marker-assisted introduction of resistance genes has been proposed as a rapid strategy to develop durable and broad-spectrum resistance in rice cultivars. The current study highlights the successful introgression of a blast resistance gene, i.e., Pi9, into CO 51, an elite rice cultivar which already has another resistance gene named Pi54. The presence of two blast resistance genes in the advanced backcross breeding materials (BC₂F_2:3) was confirmed in this study through a foreground selection method using functional markers such as NBS4 and Pi54MAS. The selected positive introgressed lines were further genotyped for background selection with 55 SSR markers that are specific to CO 51. Consequently, both Pi9 as well as Pi54 pyramided lines, with 82.7% to 88.1% of the recurrent parent genome recovery, were identified and the selected lines were evaluated under hotspot. The analysis outcomes found that both the lines possessed a high level of resistance against blast disease during the seedling stage itself. In addition to this, it was also noticed that the advanced breeding rice lines that carry Pi9 + Pi54 were effective in nature and exhibited a higher degree of resistance against blast disease compared to the lines that were introgressed with a single blast resistance gene. Thus, the current study demonstrates a rapid and a successful introgression and pyramiding of two blast resistance genes, with the help of markers, into a susceptible yet high-yielding elite rice cultivar within a short period of time. Those gene pyramided rice lines can be employed as donors to introgress the blast-resistant genes in other popular susceptible cultivars.

Engineering transcription factors (TF) hold promise in enhancing abiotic stress tolerance in plants. In this study, one of the popular rice varieties of South India, namely ADT 43, was engineered with a TF AtDREB1A driven by a stress-inducible rd29A promoter. PCR and Southern hybridization were employed to confirm the integration and copy number of the transgene. Transgenic lines (T₁) of ADT 43 showed enhanced tolerance to drought and salinity compared to the non-transgenic ADT 43. Transgenic lines were found to maintain higher RWC %, lower leaf temperature, and partially closed stomata, enabling better survival under stress conditions. qRT-PCR analysis revealed the strong induction of AtDREB1A transcripts during drought. Transgenic lines of ADT 43 exhibited increased germination and retention of chlorophyll in their leaves under salinity. Evaluation of transgenic lines under transgenic screen house conditions revealed that line # A16 exhibited on par agronomic performance against its non-transgenic counterpart under normal conditions. Under drought, non-transgenic ADT 43 showed >20% reduction in the total number of spikelets per panicle, whereas transgenic line # A16 registered only a 2% reduction. Non-transgenic ADT 43 recorded 80% yield reduction under drought, whereas line # A16 recorded only 54% yield loss. The above results demonstrated the effectiveness of controlled expression of DREB1A in regulating dehydration responses in rice.

Yams are economic and medicinal crops with a long growth cycle, spanning between 9–11 months due to their prolonged tuber dormancy. Tuber dormancy has constituted a major constraint in yam production and genetic improvement. In this study, we performed non-targeted comparative metabolomic profiling of tubers of two white yam genotypes, (Obiaoturugo and TDr1100873), to identify metabolites and associated pathways that regulate yam tuber dormancy using gas chromatography–mass spectrometry (GC–MS). Yam tubers were sampled between 42 days after physiological maturity (DAPM) till tuber sprouting. The sampling points include 42-DAPM, 56-DAPM, 87DAPM, 101-DAPM, 115-DAPM, and 143-DAPM. A total of 949 metabolites were annotated, 559 in TDr1100873 and 390 in Obiaoturugo. A total of 39 differentially accumulated metabolites (DAMs) were identified across the studied tuber dormancy stages in the two genotypes. A total of 27 DAMs were conserved between the two genotypes, whereas 5 DAMs were unique in the tubers of TDr1100873 and 7 DAMs were in the tubers of Obiaoturugo. The differentially accumulated metabolites (DAMs) spread across 14 major functional chemical groups. Amines and biogenic polyamines, amino acids and derivatives, alcohols, flavonoids, alkaloids, phenols, esters, coumarins, and phytohormone positively regulated yam tuber dormancy induction and maintenance, whereas fatty acids, lipids, nucleotides, carboxylic acids, sugars, terpenoids, benzoquinones, and benzene derivatives positively regulated dormancy breaking and sprouting in tubers of both yam genotypes. Metabolite set enrichment analysis (MSEA) revealed that 12 metabolisms were significantly enriched during yam tuber dormancy stages. Metabolic pathway topology analysis further revealed that six metabolic pathways (linoleic acid metabolic pathway, phenylalanine metabolic pathway, galactose metabolic pathway, starch and sucrose metabolic pathway, alanine-aspartate-glutamine metabolic pathways, and purine metabolic pathway) exerted significant impact on yam tuber dormancy regulation. This result provides vital insights into molecular mechanisms regulating yam tuber dormancy.

The increased use of chemicals in rice farming poses significant issues regarding the emergence of pesticide/fungicide resistance and environmental sustainability concerns. This study was aimed at the genetic improvement of blast, bacterial leaf blight (BB) and gall midge resistance in a popular rice variety CO 51 which already harbours a blast resistance gene Pi54. Efforts were made to pyramid an additional blast resistance gene Pi9 along with two BB resistance genes (xa13 and Xa21) and two gall midge resistance genes (Gm1 and Gm4) into an elite rice variety CO 51 to enhance the resistance level to biotic stresses. The superior lines were selected using functional markers conferring resistance to blast (NBS4 and Pi54MAS linked to Pi9 and Pi54 genes, respectively) and BB [(xa13Prom (xa13) and pTA248 (Xa21)] and SSR markers linked to Gm1 (RM1328) and Gm4 (RM22550) for phenotypic screening and agronomic evaluation. The genotyping and phenotyping of F₆ and BC₂F₆ progenies of CO 51 X 562-4, for agronomic traits and resistance to BB and blast, identified ten superior progenies in F₆ and five superior progenies in BC₂F₆. The breeding lines harbouring both xa13+Xa21 exhibited high levels of resistance to BB (score ≤ 1 cm) and Pi9+Pi54 exhibited strong resistance to blast (score ≤ 2). Identified lines can be evaluated further for varietal improvement or utilised as genetic stocks in breeding programs.