KC Bansal1, Kutubuddin A. Molla2, and Sonia Goel3
1 The Alliance of Bioversity International and CIAT, Asia, India, New Delhi
2 ICAR-National Rice Research Institute, Cuttack
3 SGT University, Gurugram
Corresponding Author: kcbansal27@gmail.com
Genome or gene editing mediated by CRISPR-Cas system has emerged as a powerful tool with a capability of precisely mutagenizing the genome of a wide range of organisms. The technology is based on an existing bacterial immune system, and is accepted and applied world-wide as a simple, precise and efficient method to genetically improve living organisms including animal and plant species for agriculture, food and nutrition.In addition, the CRISPR-mediated genome editing has the potential for developing safe and cost-effective plant-based vaccines for COVID-19. The technology has already been applied for basic biological research, human therapeutics, and crop improvement.
India is well poised for using CRISPR-based Genome Editing for improving crops with traits such as abiotic and biotic stress tolerance, herbicide tolerance, nutritional quality, and more. This was revealed in the recently concluded Hands-on Workshop on Genome Editing organized jointly by The Alliance of Bioversity International and CIAT, Asia-India, New Delhi and the SGT University, Gurugram,in collaboration with ICAR institutes such as National Rice Research Institute, Cuttack; National Institute of Plant Biotechnology, New Delhi, and the DBT’s National Agri-food Biotechnology Institute, Mohali, from March 23 -27, 2021.
The objective of the workshop was to develop skilled human resources and capacity building for efficient use of this latest technology for crop improvement by Indian researchers.
The 5-day Hands-on Laboratory Course on CRISPR-Cas Gene Editing was attended by 14 offline and 128 online registered participants. The offline trainees were selected from various institutions of the country, which included ICAR institutes, State Agricultural Universities, Central University of Jammu, and Delhi University.
The faculty for the workshop included eminent scientists from reputed international institutions such as International Rice Research Institute (IRRI), Manila; International Institute of Tropical Agriculture (IITA), Tanzania; University of Maryland, USA; University of California, Los Angeles, USA; and Corteva Agriscience, USA in addition to the key national institutes like ICAR-Indian Agricultural Research Institute, New Delhi and CSIR- Institute of Genomics and Integrative Biology (IGIB), New Delhi.
The workshop provided for all the basic principles, concepts, and detailed know-how for applying the CRISPR-based genome editing in agriculture. Different sessions were devoted to provide relevant information to the participants on aspects such as: how to select a target gene, what tool to use to perform a desired modification, how to deliver the editing reagents into the organism, when to go for selection and screening of mutants, and what procedures and tools to use for analyzing data and validation of mutants. Although genome editing tools are highly specific, sometime they can generate unintended editing.
The experts in the workshop imparted a great deal of knowledge on minimizing such unintentional editing and, if it occurs, how to assess. Discussion on the worldwide regulatory status of genome-edited crops with particular emphasis to India was also held.
From the lectures delivered by the international faculty, it was amply clear that plant genome editing has already created crops with improved traits. For instance, generation of genome-edited rice with broad-spectrum resistance to bacterial blight by mutating the sucrose transporter gene promoters; high yielding rice by multiplex editing of three yield-related QTL genes OsGS3, OsGW2 and OsGn1a, which negatively regulate the grain size, width and weight, and number, respectively; genome edited rice with high tolerance to drought in combination with high yielding ability by mutating the ABA receptors.
Similarly, tomato has been made resistant tothe powdery mildew fungal pathogen through loss-of-function mutations in the wild-type alleles of the Mlo gene. The recent approvals of genome-edited mushroom, soybean, and petunia by the United States Department of Agriculture and CRISPR-edited tomato by Japan Govt. are significant examples of translational progress in this area that would encourage other countries including India to use CRISPR for various plant breeding innovations.
India too has already developed several genome-edited crops with improved traits such as beta-carotene enriched banana, drought and salinity tolerant rice, aromatic rice,and herbicide tolerant rice, maize and pigeon pea, and few others. However, more genome-edited crops need to be developed in the agri and horticultural sectors with diverse traits. There is a strong possibility of improving several complex agronomic traits through the use of CRISPR-mediated multiplex genome editing in a relatively short period.
India is an agrobiodiversity rich nation, and this technology is the right choice for enhanced use of the available crop diversity by bringing novel resistance genes/alleles from crop wild relatives and landraces to the cultivated gene pool for developing high-yielding climate-smart crops with enhanced resistance to emerging pests and pathogens, and tolerance to multiple stresses, such as drought, high temperature, and salinity.
Importantly, deregulation and global harmonisation of the regulatory framework is needed for commercialization of the genome-edited crops in a timely fashion for the benefit of farmers and consumers.
Advantage with CRISPR-based technology is that it permits modification of only a few bases/nucleotides in a precise and targeted manner, as against random mutagenesis attempted in the past through irradiation or chemical mutagens, for the development of crop varieties.
Notably, the genome-edited crops developed with minor targeted genetic alterations in their native genes remain indistinguishable from their non-edited counterparts and have been treated as non-GMOs in the USA and other countries. Once the CRISPR-edited plants are made transgene-free by sexual segregation, they are identical with many naturally occurringcrop genotypes. A regulatory free-pass of such edited crop plants is an absolute necessity to realize this technology’s full potential.
Feedbacks from both online and offline participants clearly indicated that this workshop helped them understand the basic concepts in applying CRISPR to their experiments, and on the types of genome modifications possible with the currently available tools, and provided information about freely accessible resources to facilitate designing and analyzing CRISPR experiments for diverse agricultural applications.
The Course Director, Prof KC Bansal expressed his views in the valedictory function, while distributing certificates to the participants, and mentioned that the availability of efficient genome engineering tools for precise editing would greatly help Indian agriculture, particularly to address the issues of climate adaptation of crops, shrinking natural resources, increasing input use-efficiency, and malnutrition. However, what is needed is a predictable, transparent, dynamic, and interactive regulatory framework to facilitate product development and commercialization on a scale similar to what India has done wonderfully well in vaccine development for COVID-19.
