摘要：
Autophagy is a primary process involved in the degradation and reuse of redundant or damaged cytoplasmic components in eukaryotes. Autophagy has been demonstrated to facilitate nutrient recycling and remobilization by delivering intracellular materials to the vacuole for degradation in plants under nutrient starvation. However, the role of autophagy in nitrogen (N) uptake and utilization remains unknown. Here, we report that the ATG6-dependent autophagic pathway regulates N utilization in tomato (Solanum lycopersicum) under low-nitrogen (LN) conditions. Autophagy-disrupted mutants exhibited weakened biomass production and N accumulation compared with wild-type (WT), while ATG6 overexpression promoted autophagy and biomass production under LN stress. The N content in atg6 mutants decreased while that in ATG6-overexpressing lines increased due to the control of N transporter gene expression in roots under LN conditions. Furthermore, ATG6-dependent autophagy enhanced N assimilation efficiency and protein production in leaves. Nitrate reductase and nitrite reductase activities and expression were compromised in atg6 mutants but were enhanced in ATG6-overexpressing plants under LN stress. Moreover, ATG6-dependent autophagy increased plant carbon fixation and photosynthetic capacity. The quantum yield of photosystem II, photosynthetic N use efficiency and photosynthetic protein accumulation were compromised in atg6 mutants but were restored in ATG6-overexpressing plants. A WT scion grafted onto atg6 mutant rootstock and an atg6 scion grafted onto WT rootstock both exhibited inhibited LN-induced autophagy and N uptake and utilization. Thus, ATG6-dependent autophagy regulates not only N uptake and utilization as well as carbon assimilation but also nutrient recycling and remobilization in tomato plants experiencing LN stress.
作者机构：
[刘峰; 杨博智; 熊程; 刘周斌; 邹学校; 徐昊; 戴雄泽; 胡博文; 欧立军; 远方; 索欢] College of Horticulture, Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Hunan Agricultural University, Changsha, 410128, China;[朱凡] College of Landscape Architecture and Art Design, Hunan Agricultural University, Changsha, 410128, China
作者机构：
[欧阳建; 彭忠; 刘洋; 李娟; 王英姿; 李适; 黄建安; 刘仲华; 欧行畅] National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients, Key Lab of Education Ministry of Hunan Agricultural University for Tea Science, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha, 410128, China;[黄纯勇] Xiangnong University Tea Industry Research Institute, Xiangxi, 416099, China
通讯机构：
[Liu, Z.; Huang, J.] N;National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients, China
作者机构：
[邹学校] Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China;[朱凡] College of Landscape Architecture and Art Design, Hunan Agricultural University, Changsha, 410128, China
通讯机构：
[Zou, X.] E;Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, College of Horticulture, Hunan Agricultural University, Changsha, China
通讯机构：
Eng. Res. Ctr. of Educ. Min. for Germplasm Innov. and Breeding New Varieties of Horticultural Crops, College of Horticulture, Hunan Agricultural University, Changsha, China
摘要：
Dear Editor, Pepper (C. annuum L.) is an important vegetable crop worldwide [1], with remarkable diversity in morphology, nutrition, color, flavor, and yield. A great effort has been made to identify quantitative trait loci (QTLs) and genes that affect these traits [2, 3]. However, few effective combinatorial events in small population sizes have limited the mapping of high-confidence QTLs for markerassisted breeding (MAB) and map-based gene cloning. The combined multi-omics approach has provided powerful tools for the rapid mining of candidate genes for MAB and for improving our understanding of candidate genes and their molecular regulation [4, 5].
作者机构：
[Yuan, Qiaoling; Xiong, Cheng; Xu, Hao; Hu, Bowen; Suo, Huan; Yang, Sha; Yuan, Fang; Pei, Zhenming; Dai, Xiongze; Zou, Xuexiao; Liu, Feng] Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University , Changsha 410125, China;[Hou, Xilin] College of Horticulture, Nanjing Agricultural University , Nanjing 210095, China;Longping Branch, Graduate School of Hunan University , Changsha 410125, China;[Zhang, Zhishuo] Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University , Changsha 410125, China<&wdkj&>College of Horticulture, Nanjing Agricultural University , Nanjing 210095, China;[Liu, Yi] Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University , Changsha 410125, China<&wdkj&>Longping Branch, Graduate School of Hunan University , Changsha 410125, China
通讯机构：
[Feng Liu] E;Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University , Changsha 410125, China
摘要：
High pollen fertility can ensure the yield and efficiency of breeding work, but factors that affect the fertility of pepper pollen have not been studied extensively. In this work, we screened the reduced pollen fertility 1 (rpf1) mutant of Capsicum annuum with reduced pollen fertility and yellow anthers from an EMS (ethyl methanesulfonate)-mutagenized pepper population. Through construction of an F2 population followed by BSA (bulked segregant analysis) mapping and KASP genotyping, we identified CabHLH1 as a candidate gene for control of this trait. A G → A mutation at a splice acceptor site in CabHLH1 causes a frameshift mutation in the mutant, and the translated protein is terminated prematurely. Previous studies on CabHLH1 have focused on the regulation of flavonoid synthesis. Here, we found that CabHLH1 also has an important effect on pollen fertility. Pollen vigor, anther flavonoid content, and seed number were lower in CabHLH1-silenced pepper plants, whereas anther H2O2 and MDA (malondialdehyde) contents were higher. RNA-seq analyses showed that expression of the flavonoid synthesis genes DFR, ANS, and RT was significantly reduced in anthers of CabHLH1-silenced plants and rpf1 plants, as was the expression of DTX35, a gene related to pollen fertility and flavonoid transport. Yeast one-hybrid and dual-luciferase reporter assays showed that CabHLH1 can directly bind to the promoters of DTX35 and DFR and activate their expression. These results indicate that CabHLH1 regulates reactive oxygen species homeostasis by promoting the synthesis of anther flavonoids and acts as a positive regulator of pepper pollen fertility.
通讯机构：
Key Laboratory of Tea Science of Ministry of Education, Natl. Res. Center of Engineering and Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, China
作者机构：
[Yuanyuan C.; Tie Z.; Xuefei L.; Xiaopeng L.; Xiaochuan M.; Mengjing T.; Yuewen C.] National Center of Citrus Improvement Changsha, College of Horticulture and Landscape, Hunan Agriculture University, Changsha, 410128, China;[Bin P.] Huaihua Vocational and Technical College, Hunan, Huaihua, 418000, China;[Feifei L.] Hunan Horticultural Research Institute, Changsha, 410128, China
通讯机构：
[Xiaopeng, L.] N;National Center of Citrus Improvement Changsha, College of Horticulture and Landscape, Hunan Agriculture University, Changsha, China
通讯机构：
College of Horticulture, Hunan Agricultural University, Changsha, China
关键词：
茶叶;游离氨基酸;光谱变换;优化植被指数;多元线性回归
摘要：
不同季节的茶叶外形和品质均具有较大差异，基于植被指数检测不同季节茶鲜叶游离氨基酸含量面临着极大的挑战。本文选取了10个茶树品种3个季节（春茶、夏茶和秋茶）茶鲜叶中游离氨基酸含量数据和高光谱数据进行分析。首先，对原始光谱数据进行5种光谱变换：倒数T1/R、对数T1gR、一阶微分TR＇、倒数的一阶微分T1/R＇和对数的一阶微分T1gR＇，并进一步利用不同光谱变换优化了经典植被指数，最终比较了经典植被指数和优化植被指数对不同季节茶鲜叶游离氨基酸模型的影响。结果表明：茶鲜叶建模集和验证集游离氨基酸含量的变化趋势从大到小均为春茶游离氨基酸含量＞秋茶游离氨基酸含量＞夏茶游离氨基酸含量；光谱变换优化后的植被指数与茶鲜叶游离氨基酸的相关性均高于经典植被指数与茶鲜叶游离氨基酸相关性，相关系数绝对值范围为0.10～0.30；基于TlgR-VI构建的多元线性回归（Multiple Linear Regression，MLR）模型精度在不同季节的建模集和验证集中均得到了较好的精度，且适用于多生育时期茶鲜叶氨基酸含量的估测。基于TlgR-VI构建的全生育时期MLR具有较高的精度，建模集决定系数(Determination Coefficient，R2)和均方根误差（Root Mean Squared Error，RMSE）分别为0.38和0.72，验证模型精度R2和RMSE 分别为0.20和0.84)。本文的研究证明了光谱预处理在不同品种、不同生长季的茶鲜叶游离氨基酸检测中具有正效应，优化植被指数为茶叶品质估算提供了有益的技术支持。
