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Biology subjects

Rai, K. M.

Publications and source records attributed to Rai, K. M..

2 recordsLinked to original sources

Developmental regulators enable rapid and efficient soybean transformation and CRISPR-mediated genome editing

Soybean transformation remains challenging and has not kept pace with the rapid advancement of genetic engineering technologies due to low efficiency, lengthy timelines, and genotype dependency. Here, we developed a streamlined transformation method by leveraging developmental regulators (DRs) to promote de novo shoot regeneration directly from growing soybean plants. By evaluating multiple DR combinations, our results showed that co-expression of WUSCHEL2 (WUS2) and isopentenyltransferase (IPT) achieved higher transformation efficiencies (15.2% to 22.3%) in Williams 82 and Bert varieties than individual DRs without requiring exogenous hormones or selection agents. Moreover, this method produces heritable transgenic events within 9-11 weeks and successfully delivers CRISPR-Cas9 components, generating heritable mutations with 20% efficiency. The temporal transcriptomic and gene regulatory network analyses revealed that WUS2/IPT synergistically modulates stress responses and activates developmental pathways, orchestrating a transition from initial stress adaptation to regenerative programming. Together, our findings demonstrate that this DR-enabled approach significantly enhances soybean transformation efficiency, reduces tissue culture requirements, and offers a promising genome editing platform for soybean improvement.

plant biology↗

Drastic differential CRISPR-Cas9 induced mutagenesis influenced by DNA methylation and chromatin features

CRISPR-Cas9 mediated genome editing has been widely adopted for basic and applied biological research in eukaryotic systems. While many studies considered DNA sequences of CRISPR target sites as the primary determinant for CRISPR mutagenesis efficiency and mutation profiles, increasing evidence revealed the significant role of chromatin context. Nonetheless, most of the prior studies were limited by the lack of sufficient epigenetic resources and/or by only transiently expressing CRISPR-Cas9 in a short time window. In this study, we leveraged the wealth of high-resolution epigenomic resources in Arabidopsis thaliana to address the impact of chromatin features on CRISPR-Cas9 mutagenesis using stable transgenic plants. Our results indicated that DNA methylation and chromatin features could lead to significant variations in mutagenesis efficiency by up to 250 folds. Low mutagenesis efficiencies were mostly associated with repressive heterochromatic features. This repressive effect appeared to persist through cell divisions but could be alleviated through substantial reduction of DNA methylation at CRISPR target sites. Moreover, specific chromatin features, such as H3K4me1, H3.3, and H3.1, appear to be associated with significant variations in CRISPR-Cas9 mutation profiles reflected by the 1 bp insertion rates. Our findings provided strong evidence that specific chromatin features could have significant and lasting impacts on both CRISPR-Cas9 mutagenesis efficiency and DNA double strand break repair outcomes.

plant biology↗