Pre-Inoculation water deficit effects on grapevine physiology, Xylella fastidiosa titers and Pierce’s Disease progression

Authors: Wallis, Christopher; Gorman, Zachary

Submitted to: BMC Research Notes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/17/2024
Publication Date: 4/27/2024
Citation: Wallis, C.M., Gorman, Z.J. 2024. Pre-Inoculation water deficit effects on grapevine physiology, Xylella fastidiosa titers and Pierce’s Disease progression. BMC Research Notes. 17. Article 119. https://doi.org/10.1186/s13104-024-06780-1.
DOI: https://doi.org/10.1186/s13104-024-06780-1

Interpretive Summary: In many areas where grapevines are grown plants encounter water deficit stress both due to efforts to conserve water as well as the impact of droughts. Young, newly established grapevines may in particular encounter water stress. Previous studies observed water stress imposed after inoculations with the bacterium Xylella fastidiosa greatly increases development of Pierce’s disease. This study examined the impact of chronic, pre-existing water deficit stress on grapevines prior to inoculation with X. fastidiosa to determine how that may impact the development of disease. Water stress imposed prior to X. fastidiosa inoculation did not affect bacterial titers, but greatly increased symptom development and the speed at which grapevines died. Results highlight the need to reduce X. fastidiosa vector spread in young, establishing grapevines that might be experiencing water stress.

Technical Abstract: Drought and Pierce’s disease are common throughout many grapevine-growing regions such as Mexico and the United States. Yet, how ongoing water deficits affect infections of Xylella fastidiosa, the causal agent of Pierce’s disease, is poorly understood. Symptoms were observed to be significantly more severe in water-stressed plants one month after X. fastidiosa inoculation, and, in one experiment, titers were significantly lower in water-stressed than well-watered grapevines. Host chemistry examinations revealed overall amino acid and phenolic levels did not statistically differ due to water deficits, but sugar levels were significantly greater in water stressed than well-watered plants. Results highlight the need to especially manage Pierce’s disease spread in grapevines experiencing drought.