Genome-Wide Identification of CsATGs in Tea Plant and the Involvement of CsATG8e in Nitrogen Utilization.

Wei Huang,Dan-Ni Ma,De-Jiang Ni,Hong-Ling Liu,Yu Wang,Fei Guo,Ming-Le Wang,Jie Luo,Hua Zhao,Pu Wang

doi:10.3390/ijms21197043

Abstract

Nitrogen (N) is a macroelement with an indispensable role in the growth and development of plants, and tea plant (Camellia sinensis) is an evergreen perennial woody species with young shoots for harvest. During senescence or upon N stress, autophagy has been shown to be induced in leaves, involving a variety of autophagy-related genes (ATGs), which have not been characterized in tea plant yet. In this study, a genome-wide survey in tea plant genome identified a total of 80 Camellia Sinensis autophagy-related genes, CsATGs. The expression of CsATG8s in the tea plant showed an obvious increase from S1 (stage 1) to S4 (stage 4), especially for CsATG8e. The expression levels of AtATGs (Arabidopsis thaliana) and genes involved in N transport and assimilation were greatly improved in CsATG8e-overexpressed Arabidopsis. Compared with wild type, the overexpression plants showed earlier bolting, an increase in amino N content, as well as a decrease in biomass and the levels of N, phosphorus and potassium. However, the N level was found significantly higher in APER (aerial part excluding rosette) in the overexpression plants relative to wild type. All these results demonstrated a convincing function of CsATG8e in N remobilization and plant development, indicating CsATG8e as a potential gene for modifying plant nutrient utilization.

Highlights

We examined the biomass of roots (Root), rosettes (Rosette) and aerial part excluding rosette (APER), and a decrease was observed in the biomass of Root, Rosette and APER in overexpression Arabidopsis (OE) plants versus wild type (WT) plants (Figure 5c)
Considering that the buds or the tender leaves are usually harvested in tea plant, while in Arabidopsis, the APER came up after rosette formation, we investigated the biomass allocation in aerial part and defined biomass allocation in APER as APER/(APER + Rosette) in this study
The results indicate that the CsATG8e OE lines outperform the WT plants in amino N content in all the three N regimes from deficiency to sufficiency

Summary

Introduction

Nitrogen (N) is one of the most important contributors for tea plant growth and leaf quality due to the harvest of leaves several times a year [2]. Pruning is usually performed by the end of plucking season, leading to the removal of a significant amount of N. All this suggests a huge demand of N in tea plantation. To solve this demand, excessive N is usually fertilized to maintain the vigorous growth and tea yield, resulting in many environmental problems [3,4]. Apart from the uptake of N from soil as well as foliar, N remobilization within plants plays an important role in meeting the demand of young leaves. Under insufficient N conditions, N remobilization becomes a more important N source for growing shoots [7]

Methods

Results

Conclusion