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<p class="MsoNormal"><span style="font-size:11.0pt">Dear all,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Please join us in Marley 230 at 4:00 PM today for a seminar presented by Dr. Jesse Woodson.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><a href="https://arizona.zoom.us/j/83044711714?pwd=IQ994mWIPwbsRKMnfF9sERx5sNtv4m.1">Zoom link</a>: https://arizona.zoom.us/j/83044711714 (password: SPLS24).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Refreshments will be provided in the Marley Lobby at 3:30 PM.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt">How plants respond to stress: Cellular signaling and whole-plant coordination
<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt">Abstract</span></b><span style="font-size:11.0pt">: To thrive as sessile organisms, plants must be able to sense and respond to their dynamic environments. Plants achieve this by using intracellular signaling
networks that initiate local responses to stress. At the same time, these stresses can induce mobile signals that rapidly travel through the plant to control distal responses and stress acclimation. In many cases, stress sensing and signal initiation are controlled
by photosynthetic chloroplast organelles. This is due, in part, to photosynthesis naturally producing reactive oxygen species (ROS) such as singlet oxygen, superoxide, and hydrogen peroxide. Under environmental stresses (e.g., drought, excess light, extreme
temperatures, and pathogen attack), photosynthetically produced ROS can induce signals controlling gene expression, chloroplast degradation, programmed cell death, and long-distance stress acclimation (a.k.a. systemic acquired acclimation). The existence of
such signals has been known for decades, but the molecular mechanisms controlling them have remained obscure. To understand how these signals are initiated, propagated, and ultimately affect local and whole-plant plant physiology, my group has combined genetics,
cell biology, and molecular biology to identify and characterize chloroplast ROS signaling pathways. This work involves performing forward genetic screens in
<i>Arabidopsis thaliana</i> to identify mutations that block chloroplast ROS signaling. We then identify and characterize the mutated genes to determine their signaling roles. This work has greatly increased our understanding of how these signals are propagated,
revealing roles for plastid gene expression, post-translational modifications, and hormone signaling. We have also used microscopy techniques to measure the effects of these signals on cell structure, revealing new roles for cellular turnover machinery. At
the same time, my group has begun investigating how these signals are transduced through plants to control distal gene expression and stress acclimation. This has involved developing molecular tools to initiate localized ROS bursts and to measure the propagation
of electrochemical waves (ROS and calcium ions) that transmit this information to distal tissue. Such technology can ultimately be used to open bi-directional communication with plants: 1) sentinel plants that report on their health, which can lead to improved
crop management strategies, and 2) molecular tools that will allow us to potentiate whole-plant stress responses to improve crop quality and yield.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:10.0pt;font-family:"Courier New";mso-ligatures:none">===============================================================<br>
</span><b><span style="font-size:20.0pt;font-family:"Vladimir Script";mso-ligatures:none">Zhongguo Xiong</span></b><span style="font-size:10.0pt;font-family:"Courier New";mso-ligatures:none"> <br>
School of Plant Sciences BIO5 Institute<br>
BIO5 Email: <span style="color:blue"><a href="mailto:zxiong@arizona.edu"><span style="color:blue">zxiong@arizona.edu</span></a></span>
<br>
Phone: (520)-621-9869<br>
Forbes 303, P.O. box 210036 Fax: (520)-621-7186<br>
University of Arizona <br>
Tucson, AZ 85721-0036 <span style="color:blue"><a href="http://ag.arizona.edu/~zxiong"><span style="color:blue">http://ag.arizona.edu/~zxiong</span></a></span><br>
===============================================================</span><span style="font-size:11.0pt;mso-ligatures:none"><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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