Plants
regulate responses to their environment through complex hormone signaling;
these hormones can be categorized broadly into two categories: growth and
defense, though many have roles in both. Much remains to be understood about
the complexity of hormone signaling in relation to environmental responses,
especially species- and genotype-specific differences. Unraveling this
complexity of hormone signaling will lead to the development of resilient crops
that are able to respond appropriately to their environment. In this dissertation,
I hypothesize novel roles for growth and defense hormones in <i>Solanum </i>spp. responses to 1) biochar, a
black carbon soil amendment (Chapter 2), 2) infection with<i> Ralstonia solanacearum</i>, an economically important soilborne
pathogen causing bacterial wilt (Chapter 3), and 3) endophytic colonization by
the soil bacterial community (Chapter 4). In Chapter 2, I showed that biochar
upregulates GA signaling and affects GA-related traits in a species- and
cultivar-specific manner. Biochar amendment also downregulates defense
signaling. In Chapter 3, I demonstrated a novel role for auxin in resistance
against <i>R. solanacearum, </i>including
differential expression of auxin signaling genes in resistant genotype H7996
compared to susceptible WV in response to <i>R.
solanacearum</i> infection. In addition, I observed stronger and faster
upregulation of defense hormone marker genes for SA and ET in H7996 compared to
WV. In Chapter 4, I showed that SA and ET are required for normal tomato root
microbial community assembly, affecting the colonization of a few key taxa in
order to promote alpha diversity. H7996 and WV root communities differ in alpha
diversity, and a panel of H7996 x WV RILs showed quantitative variation in
alpha diversity that correlated negatively with the abundance of these key
taxa. In conclusion, I elucidated novel roles for hormones in responses to the
soil environment, pathogen infection, and root community colonization. These
findings are important for developing resilient, sustainable crops.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/7416437 |
| Date | 17 January 2019 |
| Creators | Elizabeth A. French (5929676) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/PLANT_HORMONE_PATHWAYS_PLAY_A_CRUCIAL_ROLE_IN_SOLANUM_SPP_INTERACTIONS_WITH_THE_SOIL_ENVIRONMENT/7416437 |
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