Poster: Environmental physiology

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Abs # P01004: New perspectives on the acclimation of maize plants to CO₂ enrichment

Presenter:	Prins, Anneke       Contact Presenter
Authors	Prins, Anneke  (A) (B)  Driscoll, Simon P (A)   Verrier, Paul  (C)   Kunert, Karl  (B)   Foyer, Christine H (A)
Affiliations:	(A): Crop Performance and Improvement Division, Rothamsted Research (B): FABI, Botany Department, (C): Biomathematics and Bioinformatics Division, Rothamsted Research

Atmospheric change presents multiple challenges for the sustainable management of agricultural ecosystems. We have examined the physiological and genetic responses of C₄ plants to rising atmospheric CO₂. Maize plants benefit from growth with CO₂ enrichment. Moreover, photosynthesis is regulated differently on the adaxial and abaxial sides of the leaf in response to increasing CO₂ (Driscoll et al. (2006) J. Expt. Bot 57: 381-390).While one side of the maize leaf shows classic C₄ type response to changes in CO₂ availability, the other displays responses that are indicative of C₃ photosynthesis. The leaf transcriptome was compared in young and senescent maize leaves from plants grown to maturity either in air (350 ppm) or with CO₂ enrichment (700 ppm) to identify novel proteinases and proteinase inhibitors that control senescence and high CO₂ responses. The effect of CO₂ enrichment on the transcriptome was small compared to that of senescence. High CO₂ induced a change in the abundance of only 90 transcripts in young fully developed green leaves while 142 transcripts were modified in senescent leaves subjected to the same treatments. Of these, 18 high CO₂- modified transcripts were identical in both young and senescent leaves. We conclude that these sequences are specifically affected by CO₂ enrichment rather than plant development. In contrast, over 3000 transcripts were differentially expressed in senescent leaves compared to young leaves regardless of the CO₂ enrichment. Moreover, nearly 2500 of these sequences were identical in plants grown in air and with CO2 enrichment. We conclude that these transcripts are specifically regulated by development, regardless of the CO₂ environment. The high CO₂ transcriptome displayed a signature indicative of oxidative stress.