b'Zait looks at an imageNext Up: Smarter Guard Cellsvisible from theThe discovery of sugars and maleic acid as mes-microscope showingsengers has opened a new field of questions for one or two (depending on theAssmanns lab. One major focus now is how guard image) pairs of guardcells integrate multiple types of environmental sig-cells and thenals beyond lightsuch as humidity, carbon diox-encircled stomatalide concentration and drought-related hormones.pore.PHOTO: PENN STATE UNIVERSITYBy solving one of plant biologys longest-run-ning mysteries, Assmann and her colleagues are laying the groundwork for a future where crops are not only more efficient but also more resilienta vital goal for seed companies and growers alike.Yotam Zait performed extensive experiments for the Nature Plants article as a post-doc in Assmanns lab. He (and additional lab members) then performed additional experiments after he took up his position as an assistant professor at the Hebrew University, Faculty of Agriculture, Rehovot, Israel."In regions where water is the main limiting factor for agriculture, understanding how plants fine-tune the balance between carbon gain and water loss is key to ensuring future food security," Yotam says.Assmann says the next big question is how guard cells integrate these mesophyll messenger signals with other signals that this specialized cell type also perceives.An analogy would be if cells in the retinas of our eyes could not only see but also taste and smell, she says. How guard cells integrate all this information in the regulation of stomatal apertures is an ongoing question that has fascinated stoma-tal physiologists for years.The teams research, conducted on mouse-ear cress (pictured) and fava beans, orAs the seed industry looks for deeper biologi-Vicia faba, revealed that sugars, along with maleic acid, a chemical involved incal understanding to support next-generation energy production, act as crucial messengers that control how and when plantstraits, discoveries like this offer a rare combina-breathe and eat. PHOTO: SARAH ASSMANN tion of scientific elegance and practical relevance. Whether used to engineer new varieties, speed up The discovery could also improve phenotyping technologies. With 448trait selection or build more climate-adaptive crop-metabolites now cataloged from apoplastic fluid, researchers and breedersping systems, the molecular messengers identi-have a new set of potential biomarkers for screening stomatal behavior andfied in this study could help determine howand stress resilience. These biological insights could be integrated into digital plat- whethercrops thrive in the decades to come.forms and predictive models for faster trait evaluationstreamlining the seedThe Penn State team included doctoral stu-development pipeline from lab to field. dent Yunqing Zhou, Associate Professor of Were focused on understanding how plants sense and respond to envi- Biology Timothy Jegla, and postdoctoral schol-ronmental conditions, Assmann says. Plants cant uproot themselves andars Mengmeng Zhu and Additional collaborators find somewhere else to live; they have to deal with whatever the environmentcame from institutions in Japan, Israel and the throws at themincreasingly drought and heat stressso we study whatUniversity of Mississippi. The U.S. National Science makes plants resilient, from the very specific molecular level all the way up toFoundation funded the Penn State portion of the whole plant physiology and field experiments, with the goal of improving cropresearch.SWproductivity.34/ SEEDWORLD.COMDECEMBER 2025'