Proteomics analysis reveals marker proteins for minor vein initiation in rice leaf.

Leaf veins play a critical role in resource supplication and photosynthate translocation; thus, it is considered as an important agricultural trait for crop breeding. The rice minor veins are parallelly grown along all the parts of the leaf from base to tip. To understand the process of minor vein development, anatomy analysis was performed to reveal the initiation and development of minor veins in rice leaf. The frequency of minor vein initiation follows a decreased tendency from leaf base to tip. An iTRAQ-based proteomics analysis was performed in rice leaf sections. Photosynthesis- and carbon fixation-related proteins accumulated a high level in the middle part of leaves. Furthermore, marker proteins involved in sucrose degradation and starch synthesis were accumulated into initiation and mature parts of minor veins, respectively. It suggests a different source-sink activity in the initiation and mature parts of minor veins in terms of photosynthate translocation. The identified proteins are candidate markers for small vein initiation in rice leaves.