{"id":2547,"date":"2024-03-21T14:09:00","date_gmt":"2024-03-21T14:09:00","guid":{"rendered":"https:\/\/new.www.purdue.edu\/newsroom\/?p=2547"},"modified":"2024-06-12T14:15:13","modified_gmt":"2024-06-12T14:15:13","slug":"decoding-the-plant-worlds-complex-biochemical-communication-networks","status":"publish","type":"post","link":"https:\/\/www.purdue.edu\/newsroom\/2024\/Q1\/decoding-the-plant-worlds-complex-biochemical-communication-networks","title":{"rendered":"Decoding the plant world\u2019s complex biochemical communication networks"},"content":{"rendered":"

WEST LAFAYETTE, Ind. —<\/p> \n

A Purdue University-led research team has begun translating the complex molecular language of petunias. Their grammar and vocabulary are well hidden, however, within the countless proteins and other compounds that fill floral cells.<\/p>\n<\/div>\n\n\n

Being rooted to the ground, plants can\u2019t run away from insects, pathogens or other threats to their survival. But plant scientists have long known that they do send warnings to each other via scent chemicals called volatile organic compounds.<\/p>\n\n\n\n

\u201cThey use volatiles because they can\u2019t talk,\u201d said Natalia Dudareva<\/a>, Distinguished Professor of Biochemistry<\/a> and Horticulture and Landscape Architecture<\/a> at Purdue. \u201cPlants inform neighboring plants about pathogen attacks. It looks almost like immunization. Under normal conditions, you don\u2019t see any changes in the receiver plant. But as soon as a receiver plant is infected, it responds much faster. It\u2019s prepared for response.\u201d<\/p>\n\n\n\n

Plant scientists have long known about this immunization-like priming, but until a few years ago, they had no way to study the process. They needed a marker showing that the plants had detected the volatile compounds.<\/p>\n\n\n\n

Dudareva and 13 co-authors describe new details of the detection process in the March 22, 2024, issue of the journal Science<\/a>. The team includes researchers from Purdue; Universit\u00e9 Jean Monnet Saint-Etienne in France; and the University of California, Davis.<\/p>\n\n\n

\n
\"Petunias\"
A research team led by Purdue University scientists has documented new details about how petunias use volatile organic compounds to communicate. (Purdue Agricultural Communications photo\/Tom Campbell)<\/figcaption><\/figure>\n<\/div>\n\n\n

Scientists know little about plant receptors for volatiles. Mammals and insects have them, too, but the way they perceive volatiles is too different to help researchers study the process in plants, Dudareva said.<\/p>\n\n\n\n

In 2019, in the journal Nature Chemical Biology, Dudareva and her associates published their discovery of a new physiological process, \u201cNatural fumigation as a mechanism for volatile transport between flower organs.\u201d<\/a> The study described how a plant\u2019s floral tubes produce volatile compounds to sterilize their stigma, the part of the pistil that collects pollen, to protect against attack by pathogens.<\/p>\n\n\n\n

\u201cThere are a lot of sugars on the stigma, especially in petunias. It means that bacteria will grow very nicely without these volatiles present,\u201d Dudareva said. \u201cBut if the stigma does not receive tube-produced volatiles, it\u2019s also smaller. This was interorgan communication. Now we had a good marker \u2014 stigma size \u2014 to study this communication process.\u201d<\/p>\n\n\n\n

Measurements made from photographs showed statistical differences in the stigma size upon exposure to volatiles, said the Science study\u2019s lead author, Shannon Stirling, a PhD student in horticulture and landscape architecture at Purdue. \u201cYou can see that this is a consistent trend,\u201d she said. \u201cOnce you\u2019ve looked at enough stigmas, you can see by eye that there is a slight difference in size.\u201d<\/p>\n\n\n\n

Combined with the genetic manipulation of the potential proteins involved, the work surprisingly revealed that a karrikin-like signaling pathway played a key role in petunia cellular signaling.<\/p>\n\n\n\n

\u201cKarrikins aren\u2019t produced by plants,\u201d Stirling said. \u201cThey\u2019re produced when plants burn, and our plants have never been exposed to smoke or fire.\u201d<\/p>\n\n\n\n

The team also documented the importance of the karrikin-like pathway in the detection of volatile sesquiterpenes. Many plants use sesquiterpenes to communicate with other plants, among other functions.<\/p>\n\n\n\n

Surprisingly, the identified karrikin receptor showed the ability to selectively perceive signaling from one type of sesquiterpene compound but not its mirror image, a trait called \u201cstereospecificity.\u201d The receptor appears to be highly selective to the compound, said study co-author Matthew Bergman, a postdoctoral researcher in biochemistry at Purdue.<\/p>\n\n\n\n

\u201cThe plant produces many different volatile compounds and is exposed to plenty of others,\u201d Bergman said. \u201cIt\u2019s quite remarkable how selective and specific this receptor is exclusively for this signal being sent from the tubes. Such specificity ensures that no other volatile signals are getting by. There\u2019s no false signaling.\u201d<\/p>\n\n\n\n

For Stirling, the study required mastering a painstaking method for temporarily altering the levels of proteins of the petunia pistils to identify the signal-receptor protein interactions. \u201cPistils and stigmas are small. They\u2019re a little difficult to work with because of their size,\u201d she said. \u201cEven the sheer amount of stigmas you need to get enough sample for anything is quite large because they don\u2019t weigh much.\u201d<\/p>\n\n\n\n

This method involved injecting a certain species of bacterium into the stigma to introduce targeted genes, then isolating the resulting proteins.<\/p>\n\n\n\n

\u201cIt\u2019s not easy to manipulate such a small organ,\u201d Bergman noted. \u201cBut Shannon was able to gently prick the stigma with a syringe and infiltrate it with this bacterium so delicately. She\u2019s quite an expert at this.\u201d<\/p>\n\n\n\n

Petunias are often brightly colored and smell nice, but the Purdue scientists also value them because they serve as a fertile model system for their research.<\/p>\n\n\n\n

\u201cThey\u2019ve proven quite fruitful thus far,\u201d Bergman said.<\/p>\n\n\n\n

This work was funded by the National Science Foundation, the USDA National Institute of Food and Agriculture, and the National Institutes of Health.<\/p>\n\n\n\n

About Purdue University<\/h2>\n\n\n\n

Purdue University is a public research institution demonstrating excellence at scale. Ranked among top 10 public universities and with two colleges in the top four in the United States, Purdue discovers and disseminates knowledge with a quality and at a scale second to none. More than 105,000 students study at Purdue across modalities and locations, including nearly 50,000 in person on the West Lafayette campus. Committed to affordability and accessibility, Purdue\u2019s main campus has frozen tuition 13 years in a row. See how Purdue never stops in the persistent pursuit of the next giant leap \u2014 including its first comprehensive urban campus in Indianapolis, the new Mitchell E. Daniels, Jr. School of Business, and Purdue Computes \u2014 at https:\/\/www.purdue.edu\/president\/strategic-initiatives<\/a>. <\/p>\n","protected":false},"excerpt":{"rendered":"

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