P1227Somatogenetic Interactions Alter Drought Response in Grafted Plants
James Crabb, Magnus Wood, Helmut Kirchhoff, Amit Dhingra
Grafting is known to induce a wide variety of changes in crop growth and development that could be employed to improve crop quality and production efficiency. Somatogenetic interactions across the graft union have been observed to modulate disease resistance and plant physiology, including biotic and abiotic stresses. The first hypothesis of this project is that grafting impacts the drought tolerance of a crop and the second hypothesis is that the somatogenetic alterations in the scion are caused by transfer of rootstock-derived RNA across the graft union. Non-invasive measurements of plant water status and photosynthetic performance were made using in situ leaf psychrometers and high-throughput fluorescence imaging, respectively. The data were used to quantify the response of reciprocally grafted and non-grafted tomato plants to reduced soil water content and re-watering in two varieties that have been previously reported as being sensitive or tolerant to drought stress. Quantitative changes in the transcriptomes between different stages of drought are expected to result in the identification of genes that are involved in altered drought response. The changes in gene expression will be validated using qRT-PCR. Plant water status and photosynthetic performance changed in the reciprocally grafted tomato plants compared to self-rooted control plants under water limiting conditions. This indicates that grafting is potentially useful in combating the negative effects of limiting water availability. Further, identification of the molecular signals involved in mediating drought response across the graft union is expected to provide an understanding of the underlying mechanism.