Differential protein analysis of pecan hardwood cuttings

Authors: CAO, FAN - Nanjing Forestry University; Wang, Xinwang; LIU, ZHUANGZHUANG - Nanjing Forestry University; LI, YONGRONG - Nanjing Forestry University; PENG, FANGREN - Nanjing Forestry University

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2019
Publication Date: 9/1/2019
Citation: Cao, F., Wang, X., Liu, Z., Li, Y., Peng, F. 2019. Differential protein analysis of pecan hardwood cuttings. HortScience. 54(9):1551-1557. https://doi.org/10.21273/HORTSCI13776-18.
DOI: https://doi.org/10.21273/HORTSCI13776-18

Interpretive Summary: Currently, pecan orchard establishment is dependent upon grafting wood onto rootstocks or seed-stocks. However, 3-5 years are required to grow rootstocks or seed-stocks suitable for grafting, and another 5-8 years are required for the grafted trees to produce nuts. Pecan cuttings are difficult to root. This study describes the pecan hardwood rooting process based on anatomical characteristics to understand root formation mechanisms of pecan cuttings. The preliminary data provide a basis for speeding up pecan propagation and ultimately to increase pecan production.

Technical Abstract: Pecan cuttings are difficult for rooting. This study describes the pecan hardwood rooting process based on anatomical characteristics to understand root formation mechanisms of pecan cuttings. Furthermore, the expressed proteins of different periods during the adventitious rooting process of pecan seedling hardwood cutting were identified and analyzed to evaluate the rooting mechanism, and the expressed proteins of the seedling were also compared with the cultivar’s in the rooting key period. In the study, Pecan seedling cuttings were developed at different air and substrate temperatures in order to induce roots. The adventitious root formation of the pecan hardwood cuttings was described during the whole process, and the phloem of the basal part of the prepared cuttings was selected as the sample for the differential protein analysis. The results showed that the adventitious root formation of pecan hardwood cuttings was the only product of the callus differentiation, which originated from the cells of the cambium or vascular ray parenchyma. Such adventitious root primordia were developed from those calli that formed the regenerative structure, and the expressed proteins during the adventitious rooting of pecan hardwood cutting were identified and analyzed by MALDI-TOF-MS (Matrix-Assisted Laser Desorption) to evaluate the rooting mechanism. Eight differentially expressed proteins were found in the rooting periods, and 15 differential protein spots were found by the comparison of pecan cutting types, which were analyzed by peptide mass fingerprinting homology. The results show that the primordial cells were the differentiation of the meristematic cells. Furthermore, the differentially expressed proteins contained energy metabolism proteins, adversity stress proteins, and signal transmission proteins. The energy metabolism-related proteins were ATP synthase, photosynthesis-related proteins and enolase, the adversity-stress proteins contained heat shock-related proteins, and signal transmission proteins were mainly cytochrome enzymes and heme-binding protein. And the adventitious root formation of pecan cultivar hardwood cuttings was limited by high defensive protection.