Ashish Marathe

Soybean [ Glycine max (Linn.) Merr] is a globally important source of plant-based protein and edible oil, widely cultivated in India as a major oilseed crop. However, conventional breeding approaches for soybean are laborious, constrained by the genomic complexity of soybean, and face persistent challenges in genetic transformation. Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas-based genome editing has emerged as a precise and efficient tool for rapid trait improvement in soybean. While many existing reviews of soybean have been published, this literature review addresses some fundamental challenges with respect to genome editing. This study summarizes recent advancements in soybean genome editing, offering insights into the practical informatics of soybean-specific genomic databases that are required for successful construct design. It also discusses emerging technologies such as base editing, prime editing, and the increasingly important role of artificial intelligence in accelerating target identification and construct design. It highlights applications in nutritional enhancement, abiotic and biotic stress tolerance, and improvement of key agronomic traits. Beyond the conventional topics, it addresses the current regulatory landscape that researchers must navigate for releasing genome-edited varieties and provides a comprehensive perspective on practical solutions to overcome major constraints in soybean genetic engineering.

Yellow mosaic disease of Cajanus scarabaeoides (L.) Thouars (CsYMD) was observed in up to 46% of C. scarabaeoides plants in the mungbean, urdbean, and pigeon pea fields from 22 districts of Chhattisgarh State, India, during 2017 to 2019. The symptoms were characterized by yellow mosaic on green leaves and yellow discoloration of leaves in advanced stages of the disease. Severely infected plants showed shortened internodal length and reduced leaf size. CsYMD was transmissible to healthy C. scarabaeoides and C. cajan by whitefly (Bemisia tabaci). The infected plants developed typical yellow mosaic symptoms on their leaves within 16 and 22 days of inoculation, respectively, suggesting a begomovirus etiology. Molecular analysis revealed that this begomovirus has a bipartite genome composed of DNA-A (2,729 nucleotides) and DNA-B (2,630 nucleotides). Sequence and phylogenetic analyses revealed that the nucleotide sequence of the DNA-A component had the highest identity of 81.1% with DNA-A of Rhynchosia yellow mosaic virus (RhYMV; NC_038885), followed by mungbean yellow mosaic virus (MN602427; 75.3%). DNA-B had the highest identity of 74.0% with DNA-B of RhYMV (NC_038886). As per ICTV guidelines, this isolate had <91% nucleotide identity with DNA-A of any of the begomoviruses reported; so, it is proposed as a new begomovirus species, tentatively named C. scarabaeoides yellow mosaic virus (CsYMV). After agroinoculation with DNA-A and DNA-B clones of CsYMV, all Nicotiana benthamiana plants developed leaf curl symptoms along with light yellowing symptoms 8 to 10 days after inoculation (DAI), while ∼60% of the C. scarabaeoides plants developed yellow mosaic symptoms similar to those observed in the field 18 DAI, thus fulfilling Koch’s postulates. From these agro-infected C. scarabaeoides plants, CsYMV was transmissible to healthy C. scarabaeoides plants by B. tabaci. Apart from these hosts, CsYMV also infected and caused symptoms in mungbean and pigeon pea.