Discovery allows early detection of shade avoidance syndrome

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December 21, 2020

Researchers from SMART built a tabletop Raman spectroscopy instrument that allows measurement of carotenoid levels in plants, which can indicate whether a plant has shade avoidance syndrome. Image courtesy of the Singapore-MIT Alliance for Research and Technology.

Singapore-MIT Alliance for Research and Technology

Researchers from the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) Interdisciplinary Research Group within the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, and Temasek Life Sciences Laboratory (TLL) have discovered a way to use Raman spectroscopy for early detection of shade avoidance syndrome (SAS) in plants. The discovery can help farmers with timely intervention against SAS, leading to better plant health and crop yield.

SAS is an adaptive response and an irreversible phenomenon, where plants reach for more light to overcome shaded conditions. It is commonly seen in plants experiencing vegetative shade, which is detrimental to plant health, as it leads to a number of issues including hindrance of leaf development, early flowering, and weakening of the plant’s structure and immune system.

Thus, early detection of SAS is key for sustainable agriculture and improved crop yield. However, existing methods for detecting SAS are restricted to observing structural changes, making it difficult to detect early.

In a paper titled “Rapid metabolite response in leaf blade and petiole as a marker for shade avoidance syndrome,” published in the journal Plant Methods, SMART DiSTAP and TLL scientists explain their new way of detecting SAS in time for farmers to intervene to prevent the irreversible effects of SAS. The team built a tabletop Raman spectroscopy instrument that allows measurement of carotenoid levels in plants, which can indicate whether a plant has SAS.

“Our experiments with Raman spectroscopy detected a decrease in the carotenoid contents of plants that have SAS,” says Gajendra Pratap Singh, co-first author of the paper and scientific director and principal investigator at DiSTAP. “While plants with longer exposure to shade developed more severe SAS, these morphological changes were only seen after one to three days. However, changes in the carotenoid peak intensities were detected much earlier, from just four hours of shade treatment.”

Using Raman spectroscopy, the scientists are able to non-destructively measure carotenoid content in the plant leaves, and have discovered its correlation to the severity of SAS and as a peak biomarker for early diagnosis. This cuts down the time taken to detect SAS from days to a matter of hours. The method can also be used to detect SAS in plants due to high-density planting and can be particularly useful to improve urban farming practices.

“We conducted our experiments on a number of edible plants, including frequently consumed Asian vegetables like kai lan and choy sum,” says Benny Jian Rong Sng, the paper’s co-first author and PhD student from In-Cheol Jang’s group at TLL and the Department of Biological Sciences at the National University of Singapore. “Our results showed that Raman spectroscopy can be used to detect SAS induced by shade as well as high-density planting. Regardless of the food crop, this technology can be applied to improve agriculture and to meet the nutritional demands of today’s growing populations.”

In-Cheol Jang, the principal investigator at TLL and DiSTAP who led the project, says the discovery can go a long way in assisting farmers to improve urban farming practices: “We look forward to helping urban farmers achieve higher crop yields by detecting SAS within shorter time periods. By adopting scalable, precision agri-technologies like Raman spectroscopy-enabled sensors, we can better position cities like Singapore to grow more produce with less resources, while achieving desirable nutritional profiles for global food security.”

DiSTAP co-lead principal investigators Professor Chua Nam Hai of TLL and Professor Rajeev Ram of the MIT Department of Electrical Engineering and Computer Science also co-authored the article.

The research was supported by the National Research Foundation Singapore under its Campus for Research Excellence And Technological Enterprise program.

DiSTAP is one of the five SMART Interdisciplinary Research Groups. DiSTAP addresses deep problems in food production in Singapore and the world by developing a suite of impactful and novel analytical genetic and biosynthetic technologies. The goal is to fundamentally change how plant biosynthetic pathways are discovered, monitored, engineered, and ultimately translated to meet the global demand for food and nutrients.

Scientists from MIT, TTL, Nanyang Technological University, and National University of Singapore are collaboratively developing new tools for the continuous measurement of important plant metabolites and hormones for novel discovery; deeper understanding and control of plant biosynthetic pathways in ways not yet possible, especially in the context of green leafy vegetables; leveraging these new techniques to engineer plants with highly desirable properties for global food security, including high yield density production, drought and pathogen resistance and biosynthesis of high-value commercial products; developing tools for producing hydrophobic food components in industry-relevant microbes; developing novel microbial and enzymatic technologies to produce volatile organic compounds that can protect and/or promote growth of leafy vegetables; and applying these technologies to improve urban farming.

 

DiSTAP is led by MIT co-lead PI Professor Michael Strano and Singapore co-lead PI Professor Chua Nam Hai.