Engineering Crops for the Future: A Phosphoproteomics Approach

Abiotic stresses like salinity, drought, heat, metal ions, radiation and oxidative stress, and especially their combinations, are major limiting factors for growth and productivity of the crops. Various molecular and biochemical processes governing the plant responses to abiotic stresses have often been investigated and hold the key for producing high-yielding and abiotic stress-tolerant crops. Plant responses to abiotic stresses are dynamic and intricate, and vary with type, level, and duration of the stress involved, as well as on the type of tissue under stress. However, one biochemical indicator common to all stresses is definite and controlled protein phosphorylation which is generally transmitted by highly complex protein kinase cascades. In recent years, using different biochemical as well as computational tools, many of such phosphoproteins are identified and characterized with respect to abiotic stresses. Subsequently, an upsurge has been witnessed in recent times for phosphoproteomics repositories or databases. The use of this crucial knowledge about such proteins and their phosphorylation sites is one of the promising ways for crop engineering against abiotic stress. Several reports have described abiotic stress-induced transcriptome, proteome and phosphoproteome changes in plants subjected to these stress factors. However, the investigations to assess precise phosphoproteomics deviations in response to environmental stresses and their implementation for crop improvement are limited. The present review summarizes and discusses the recent developments in deciphering abiotic stress induced changes in plant phosphoproteome besides development of phosphoproteomics tools and their repositories. A critical assessment of targeting phosphoproteins for crop improvement and phosphoproteomics mediated enhanced abiotic stress tolerance in transgenic plants has been presented.