Drought-Induced Fungal Infection Causes Severe Dieback in Malosma laurina in the Santa Monica Mountains
Presentation Type
Oral Presentation
Keywords
Drought, canker, Malosma laurina, fungus, photosynthesis, Botryosphaeria dothidea
Department
Biology
Major
Biology
Abstract
The current unprecedented drought in California has reached maximums may predisposes plants to fungal infection. Dieback shrubs have shown external wounds, known as cankers, which signals the plant’s immune response to infection. The invading fungus enters through this wound; once inside, it travels through the xylem, thus blocking water transport from the soil to the leaves and thus decreasing photosynthetic rate. Our hypothesis was that photosynthetic rates in Malosma laurina will be high in healthy control resprouts, intermediate in young dieback resprouts, and low in old dieback resprouts with cankers. M. laurina, a chaparral shrub, was used because it is drought-tolerant, has deep roots, has a 99% success rate of resprouting after fires, is co-dominant with other chaparral shrub species, and is a keystone species. To test this hypothesis, a chaparral shrub, M. laurina, was monitored for photosynthesis, transpiration, water potential, conductance, electron transport rate, and ΦPSII using the LI-6400XT Portable Photosynthesis System. Study sites include next to the Theme Tower and at Drescher campus. We found that the control for both adults and resprouts had significantly higher photosynthetic rates than dieback plants. We also discovered that the fungus infecting the local shrubs is Botryosphaeria dothidea. From this, we can conclude that the fungus B. dothidea is causing dieback and thus lowering photosynthesis for infected shrubs. B. dothidea is able to infect the shrubs and cause devastation because the limited water access as a result of the drought causes the plants to be more susceptible to fungal infection.
Faculty Mentor
Dr. Stephen Davis
Funding Source or Research Program
Summer Undergraduate Research in Biology
Presentation Session
Session C
Location
Plaza Classroom 190
Start Date
1-4-2016 5:00 PM
End Date
1-4-2016 5:15 PM
Drought-Induced Fungal Infection Causes Severe Dieback in Malosma laurina in the Santa Monica Mountains
Plaza Classroom 190
The current unprecedented drought in California has reached maximums may predisposes plants to fungal infection. Dieback shrubs have shown external wounds, known as cankers, which signals the plant’s immune response to infection. The invading fungus enters through this wound; once inside, it travels through the xylem, thus blocking water transport from the soil to the leaves and thus decreasing photosynthetic rate. Our hypothesis was that photosynthetic rates in Malosma laurina will be high in healthy control resprouts, intermediate in young dieback resprouts, and low in old dieback resprouts with cankers. M. laurina, a chaparral shrub, was used because it is drought-tolerant, has deep roots, has a 99% success rate of resprouting after fires, is co-dominant with other chaparral shrub species, and is a keystone species. To test this hypothesis, a chaparral shrub, M. laurina, was monitored for photosynthesis, transpiration, water potential, conductance, electron transport rate, and ΦPSII using the LI-6400XT Portable Photosynthesis System. Study sites include next to the Theme Tower and at Drescher campus. We found that the control for both adults and resprouts had significantly higher photosynthetic rates than dieback plants. We also discovered that the fungus infecting the local shrubs is Botryosphaeria dothidea. From this, we can conclude that the fungus B. dothidea is causing dieback and thus lowering photosynthesis for infected shrubs. B. dothidea is able to infect the shrubs and cause devastation because the limited water access as a result of the drought causes the plants to be more susceptible to fungal infection.