Venkatesan Sundaresan, a Distinguished Professor of plant biology and plant sciences at the University of California, Davis, has been awarded a Gates Foundation grant to develop self-cloning crops for Indian farmers. The five-year, $4.9 million project is a collaboration with researchers Myeong-Je Cho at UC Berkeley’s Innovative Genomics Institute (IGI), Viswanathan Chinnusamy at the ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi and Ravi Maruthachalam at the Indian Institutes of Science Education and Research (IISER-Thiruvananthapuram). 

The project aims to sustainably improve agricultural productivity by producing high-yielding crops that clone themselves, allowing farmers to save their superior seeds from one season to the next. It’s based on a technology called “synthetic apomixis,” which Sundaresan’s lab previously developed in rice. 

With the new funding, the team will expand the technology into other staple crops, starting with pearl millet and Indian mustard, two crops that are regionally important in India but do not usually receive international research attention.

“It’s wonderful that the Gates Foundation has taken an interest in this technology,” said Sundaresan. “Their funding makes it possible for us to apply our method to specific crops in contexts where it can make a difference.”

Giving neglected crops the attention they deserve

Pearl millet and Indian mustard (also known as brown mustard) are widely cultivated in India, but are not traded much internationally. That means they receive less attention from funding agencies, seed developers and agricultural companies.

“Big seed companies generally want to work on huge worldwide crops like corn, soybeans and tomatoes,” said Sundaresan. “The technology we develop with this grant will directly benefit smallholder farmers in developing countries.”

Like many other crops, pearl millet and Indian mustard produce higher yields through hybrid breeding — when two genetically different varieties are crossbred. However, hybrid seeds are expensive to produce and must be purchased each year, because when hybrid plants self-fertilize, their optimal genetic combination gets scrambled, resulting in offspring with sub-par yields. 

To make hybrid crops’ high-yielding capacity stable from generation to generation, Sundaresan’s lab developed synthetic apomixis, which allows plants to clone themselves. Self-cloning hybrid varieties of pearl millet and Indian mustard will be more accessible to smallholder farmers.

Branching from grains to vegetable crops 

Sundaresan’s team originally developed synthetic apomixis in rice and has shown that the same approach can work in maize. An independent research team recently used their methods to produce self-cloning sorghum.

Extending synthetic apomixis to Indian mustard may present an additional hurdle, because it belongs to a very different branch of the plant evolutionary tree. Whereas rice, sorghum and pearl millet are all grass-like monocots, Indian mustard is a dicot in the same genus as cabbage, kale and broccoli. Because embryonic development is different in dicots, the researchers may need to significantly modify parts of their method in order to obtain self-cloning mustard. If they succeed, it will open up the possibility of using synthetic apomixis in a broad range of vegetable crops.

“It may be more complicated to move this technology into dicots, because the embryo initiation process is a little different, but I'm hoping that in five years, we'll have the technology working in Indian mustard,” said Sundaresan. “Our discoveries will also yield valuable information for other dicot crops.”

A tweak to remove transgenics 

In addition to extending synthetic apomixis to new crop species, the project aims to tweak the technology so that it no longer involves transgenics — the insertion of foreign DNA from one species into another. Instead, the researchers want to develop a version of synthetic apomixis that relies exclusively on gene editing, which involves mutating or editing an organism’s existing genes using methods such as CRISPR/Cas9.

Doing so will make synthetic apomixis more widely accessible, because gene-edited crops are usually subject to less stringent regulations than transgenic crops. India recently passed laws to deregulate gene-edited crops, which means that, if successful, any self-cloning varieties produced through this project will be treated in the same way as conventionally bred varieties.

“The time is right to develop these crops in India,” said Sundaresan. “If the technology is a success there, I think it will quickly become adopted by other countries around the developing world. I'm hoping that we have, so to speak, the seeds of a new agricultural revolution in place.”