Poster Presentation 23rd Annual Lorne Proteomics Symposium 2018

Label free and TMT proteomic analysis of leaf lamina and leaf growing zones in rice genotypes with contrasting drought tolerance (#103)

Yunqi Wu 1 , Mehdi Mirzaei 1 , Paul A. Haynes 1
  1. Macquarie University, North Ryde, NSW, Australia

Plants require a distinctive cohort of enzymes to coordinate division and the subsequent expansion of cells. Proteomic analysis of ever smaller samples now enables interrogation of the proteome of tissues dissected from the leaf bases of higher plants. Thus, plants exposed to stresses such as drought are amenable to analysis of the proteome. We investigated whether proteins expressed in the mature regions as well as the most immature regions of developing leaves of a drought-tolerant rice landrace (IAC1131) could provide insights into the impact of soil drying on gene expression when compared with the drought-sensitive Nipponbare. Proteins extracted from one-cm long shoot growth zones and the mature leaf lamina were investigated using both Tandem Mass Tags (TMT) and label-free proteomic approaches. While the TMT labelling approach identified more proteins overall than the label free approach, the observed protein abundance trends and biological conclusions reached from both sets of data were in close agreement. The data acquired from both proteomic approaches indicate that the leaf lamina of IAC1131 appears to be better able to cope with stressful conditions by up-regulating a suite of stress and defence response related proteins. Nipponbare, in contrast, lacks the range of stress responses shown by the more stress tolerant variety, and responds to drought stress by initiating a partial shutdown of chlorophyll biosynthesis in an apparent attempt to preserve metabolic resources. While in the leaf growing zone, proteins involved in organization of the meristem and subsequent cell formation were up-regulated in drought in IAC1131, and those proteins involved in oxidation state and response to external stimuli were more likely to be up-regulated by drought in Nipponbare.