DTA

Digital Theses Archive

 

Tesi etd-03302023-185011

Type of thesis
Dottorato
Author
AHUMADA, GERMAN DARIO
URN
etd-03302023-185011
Title
Rice seed germination underwater: a role for endophytic bacteria
Scientific disciplinary sector
BIO/04
Course
Istituto di Scienze della Vita - PHD IN AGROBIODIVERSITY
Committee
relatore Prof.ssa PUCCIARIELLO, CHIARA
Keywords
  • Arabidopsis thaliana
  • biostimulants.
  • coleoptile
  • endophytic bacteria
  • hypoxia
  • microbiota
  • Rice
Exam session start date
12/07/2023;
Availability
parziale
Abstract
In the last decades, agriculture and food production have suffered the effects of climate change on human-driven and natural ecosystems. Germination and plant establishment suffer from extreme environmental events, including cyclones, sea level rise, and flooding caused by excessive rainfall and poor soil drainage. It has long been proposed that the use of beneficial microorganisms in farming is one of the most promising solutions to the fundamental problems of guaranteeing food security while promoting a healthy environment. Plants have complex bacterial microbiota, which is playing a role in the host&#39;s response to external factors. In addition, endophytic bacteria in plants have been shown to promote the growth of plants in different ways, including improvement in nutrient availability and boosting the production of plant hormones. However, it is still largely unclear how endophytic bacteria can affect plant germination and how they protect plants from abiotic stress.<br>In this thesis, we focused on finding seed-vectored endophytic bacteria of two rice varieties characterized by a dissimilar coleoptile phenotype. We identified the presence of a distinctive microbiota in the rice variety characterized by a long coleoptile underwater. The culturable group of putative endophytes isolated in rice seedlings exhibits plant growth-promoting activities that may influence flooding adaptabilities, such as starch hydrolysis and phytohormones production. <br>In order to increase plant fitness without utilizing agrochemicals, the isolation and identification of bacterial strains that promote plant development is an interesting opportunity. Consequently, a subgroup of rice putative endophytic bacteria was analyzed for their capacity to colonize rice plants. Finally, the complete collection of bacteria was examined for the capacity to promote plant growth using the model plant Arabidopsis thaliana. We demonstrated that some bacteria strains can increase plant biomass, lateral root number, and primary root length, indicating the need for subsequent molecular studies.<br>
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