Morphological, Physiological and Proteomic Analyses Provide Insights into the Improvement of Castor Bean Productivity of a Dwarf Variety in Comparing with a High-Stalk Variety.

Wenjun Hu,Xiaoyun Qiu,Hong Zhang,Ningjia He,Rongbin Hu,Guoxin Shen,Lin Chen,Hongling Lu,Jia Wei,Yueqing Bai,Li Sun

doi:10.3389/fpls.2016.01473

Abstract

Ricinus communis displays a broad range of phenotypic diversity in size, with dwarf, common, and large-sized varieties. To better understand the differences in plant productivity between a high-stalk variety and a dwarf variety under normal growth conditions, we carried out a comparative proteomic study between Zhebi 100 (a high stalk variety) and Zhebi 26 (a dwarf variety) combined with agronomic and physiological analyses. Over 1000 proteins were detected, 38 of which differed significantly between the two varieties and were identified by mass spectrometry. Compared with Zhebi 100, we found that photosynthesis, energy, and protein biosynthesis related proteins decreased in abundance in Zhebi 26. The lower yield of the dwarf castor is likely related to its lower photosynthetic rate, therefore we hypothesize that the lower yield of the dwarf castor, in comparing to high stalk castor, could be increased by increasing planting density. Consequently, we demonstrated that at the higher planting density in Zhebi 26 (36,000 seedlings/hm2) can achieve a higher yield than that of Zhebi 100 (12,000 seedlings/hm2). Proteomic and physiological studies showed that for developing dwarf R. communis cultivar that is suitable for large scale-production (i.e., mechanical harvesting), it is imperative to identify the optimum planting density that will contribute to higher leaf area index, higher photosynthesis, and eventually higher productivity.

Highlights

The castor bean (Ricinus communis) is a tropical perennial shrub and field crop originated in Africa, but has been introduced worldwide and is widely cultivated (Chan et al, 2010)
R. communis has been proposed as a potential source of biodiesel feedstock because of its high seed oil content (Da Silva et al, 2006), and the ease with which it can be Improvement of Castor Bean Productivity cultivated in unfavorable crop-growing environments has contributed to its appeal as a crop in tropical developing nations
The numbers assigned to the protein spots correspond to those listed in Table 5. (A) Representative Coomassie Brilliant Blue (CBB) R250-stained 2D gel of total proteins from Zhebi 100

Summary

Introduction

The castor bean (Ricinus communis) is a tropical perennial shrub and field crop originated in Africa, but has been introduced worldwide and is widely cultivated (Chan et al, 2010). It can be cross- and self-pollinated, and studies have revealed low levels of genetic variation among castor bean germplasm worldwide (Allan et al, 2008; Foster et al, 2010). R. communis has been proposed as a potential source of biodiesel feedstock because of its high seed oil content (Da Silva et al, 2006), and the ease with which it can be Improvement of Castor Bean Productivity cultivated in unfavorable crop-growing environments has contributed to its appeal as a crop in tropical developing nations. Mutation breeding has shown that irradiation of castor seeds and seedlings produces mutants with desirable characteristics including semi-dwarfs with higher yield potential and earlier maturity (Sujatha et al, 2008)

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