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.

Strategies to enhance rice productivity in response to global demand have been the paramount focus of breeders worldwide. Multiple factors, including agronomical traits such as plant architecture and grain formation and physiological traits such as photosynthetic efficiency and NUE (nitrogen use efficiency), as well as factors such as phytohormone perception and homeostasis and transcriptional regulation, indirectly influence rice grain yield. Advances in genetic analysis methodologies and functional genomics, numerous genes, QTLs (Quantitative Trait Loci), and SNPs (Single-Nucleotide Polymorphisms), linked to yield traits, have been identified and analyzed in rice. Genome editing allows for the targeted modification of identified genes to create novel mutations in rice, avoiding the unintended mutations often caused by random mutagenesis. Genome editing technologies, notably the CRISPR/Cas9 system, present a promising tool to generate precise and rapid modifications in the plant genome. Advancements in CRISPR have further enabled researchers to modify a larger number of genes with higher efficiency. This paper reviews recent research on genome editing of yield-related genes in rice, discusses available gene editing tools, and highlights their potential to expedite rice breeding programs.

Mung bean (Vigna radiata L. Wilczek) is an important short-duration grain legume; however, the development of reliable molecular approaches for studying Mungbean Yellow Mosaic Virus (MYMV) is limited for its recalcitrance to in vitro regeneration and inefficient transformation protocols. The present study aimed to optimize an Agrobacterium tumefaciens-mediated transformation and regeneration system for MYMV resistance and molecular assessment of viral transmission in mung bean cv. VBN 4. A hypocotyl-assisted wounding approach combined with pre-induced A. tumefaciens strain LBA4404 carrying MYMV infectious clones was optimized using 100 µM acetosyringone for 2 h. The optimized protocol resulted in 96.0% post-inoculation survival. Following 48 h of dark co-cultivation, MS medium supplemented with 4 mg L⁻¹ BAP, 250 mg L⁻¹ kanamycin and 200 mg L⁻¹ cefotaxime resulted in rapid shoot regeneration, with the success rate of 95.2%. Root induction with 1 mg L⁻¹ IBA resulted in 87.5% rooting, while primary and secondary acclimatization achieved 80.0% and 90.0% survival, respectively. Molecular analysis of regenerated plants confirmed MYMV infectious clones through amplification of coat protein (CP) and movement protein (MP) sequences in 88.88% of plants, while the nptII selectable marker was detected in 77.77% of regenerants. T₁ progeny showed 100% seed germination, and MYMV-specific PCR amplification was detected in 72.2% of seedlings, indicating persistence of viral sequences across generations. Overall, the optimized hypocotyl-wounding and Agrobacterium-mediated system provides a reproducible platform for controlled MYMV transformation, plant regeneration, molecular screening and investigation of viral persistence and transmission in mung bean.