Rice (Oryza sativa L. cv. IR64) was grown in split-root systems to analyze long-distance drought signaling within root systems. This in turn underpins how root systems in heterogeneous soils adapt to drought. The approach was to compare four root tissues: (1) fully watered; (2) fully droughted and split-root systems where (3) one-half was watered and (4) the other half was droughted. This was specifically aimed at identifying how droughted root tissues altered the proteome of adjacent wet roots by hormone signals and how wet roots reciprocally affected dry roots hydraulically. Quantitative label-free shotgun proteomic analysis of four different root tissues resulted in identification of 1487 nonredundant proteins, with nearly 900 proteins present in triplicate in each treatment. Drought caused surprising changes in expression, most notably in partially droughted roots where 38% of proteins were altered in level compared to adjacent watered roots. Specific functional groups changed consistently in drought. Pathogenesis-related proteins were generally up-regulated in response to drought and heat-shock proteins were totally absent in roots of fully watered plants. Proteins involved in transport and oxidation-reduction reactions were also highly dependent upon drought signals, with the former largely absent in roots receiving a drought signal while oxidation-reduction proteins were strongly present during drought. Finally, two functionally contrasting protein families were compared to validate our approach, showing that nine tubulins were strongly reduced in droughted roots while six chitinases were up-regulated, even when the signal arrived remotely from adjacent droughted roots.
Low-temperature (LT) stress is one of the major limiting factors in cereal production in cold high-altitude mountainous areas of Iran where cereals are exposed to variable periods of temperatures in the vernalization range during the autumn season. Cereals regulate their development through adaptive mechanisms that are responsive to low but nonfreezing temperatures. We exploited a proteomic approach to determine the interrelationship between vernalization fulfillment and expression of low-temperature (LT)-induced protein in most hardy Norstar and semi-hardy Azar2 wheat (Triticum aestivum L. em. Thell). These cultivars were subjected to 12 h of cold acclimating temperature (2 °C) over a period of 0-89 days. LT tolerance, as measured by LT50, and vernalization fulfillment, as estimated from final leaf number (FLN), was determined at intervals throughout the acclimation period. A significant decrease in FLN associated with LT treatment indicated that Norstar and Azar2 had vernalization responses. Azar2 achieved its vernalization fulfillment and maximum LT tolerance (∼ -8 °C) by 28 days of acclimation. However, Norstar had a longer vernalization requirement (between 35 and 42 days) and reached vernalization fulfillment and maximum LT tolerance (∼ -18.7 °C) about the same time as vernalization fulfillment. We applied a two-dimensional electrophoresis-based proteomics approach to analyze changes in the leaf proteome of two genotypes, Norstar and Azar2, during cold acclimation. Using MALDI-TOF/TOF mass spectrometry, 66 LT-associated proteins could significantly be identified. These proteins were categorized into cold-regulated proteins, antifreezing proteins, oxidative stress defense, photosynthesis, chloroplast post-transcriptional regulation, metabolisms, and protein synthesis. A close association between the vernalization fulfillment and the start of a decline in the protein accumulation of hardy Norstar with a long vernalization requirement and semi-hardy Azar2 with a short vernalization requirement was observed. This finding supported the hypothesis that developmental trait which was regulated by vernalization had a regulatory influence over LT proteome response and highlight a close link between the up-regulation of LT-associated proteins and vernalization fulfillment at the molecular level in wheat.
Infection of Mexican lime trees (Citrus aurantifolia L.) with the specialized bacterium "CandidatusPhytoplasma aurantifolia" causes witches' broom disease. Witches' broom disease has the potential to cause significant economic losses throughout western Asia and North Africa. We used label-free quantitative shotgun proteomics to study changes in the proteome of Mexican lime trees in response to infection by "Ca. Phytoplasma aurantifolia". Of 990 proteins present in five replicates of healthy and infected plants, the abundances of 448 proteins changed significantly in response to phytoplasma infection. Of these, 274 proteins were less abundant in infected plants than in healthy plants, and 174 proteins were more abundant in infected plants than in healthy plants. These 448 proteins were involved in stress response, metabolism, growth and development, signal transduction, photosynthesis, cell cycle, and cell wall organization. Our results suggest that proteomic changes in response to infection by phytoplasmas might support phytoplasma nutrition by promoting alterations in the host's sugar metabolism, cell wall biosynthesis, and expression of defense-related proteins. Regulation of defense-related pathways suggests that defense compounds are induced in interactions with susceptible as well as resistant hosts, with the main differences between the two interactions being the speed and intensity of the response.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.