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Herbivore‐induced plant volatiles (HIPVs) are critical compounds that directly or indirectly regulate the tritrophic interactions among herbivores, natural enemies and plants. The synthesis and release of HIPVs are regulated by many biotic and abiotic factors. However, the mechanism by which multiple factors synergistically affect HIPVs release remains unclear. Tea plant (Camellia sinensis) is the object of this study because of its rich and varied volatile metabolites. In this study, benzyl nitrile was released from herbivore‐attacked tea plants more in the daytime than at night, which was consistent with the feeding behaviour of tea geometrid (Ectropis grisescens Warren) larvae. The Y‐tube olfactometer assay and insect resistance analysis revealed that benzyl nitrile can repel tea geometrid larvae and inhibit their growth. On the basis of enzyme activities in transiently transformed Nicotiana benthamiana plants, CsCYP79 was identified as a crucial regulator in the benzyl nitrile biosynthetic pathway. Light signalling‐related transcription factor CsPIF1‐like and the jasmonic acid (JA) signalling‐related transcription factor CsMYC2 serve as the activator of CsCYP79 under light and damage conditions. Our study revealed that light (abiotic factor) and herbivore‐induced damage (biotic stress) synergistically regulate the synthesis and release of benzyl nitrile to protect plants from diurnal herbivorous tea geometrid larvae. Summary statement: Tea geometrid‐induced volatile benzyl nitrile (BN) emission has a diurnal pattern, which is consistent with the feeding of tea geometrids. Light and damage induce the emission of BN and the CsCYP79 expression which is promote by the CsMYC2 and CsPIFs‐like. [ABSTRACT FROM AUTHOR]

Lingtou Dancong oolong tea is a famous Chinese oolong tea due to its special honey-like aroma. However, little is known about its specific aroma profile and key contributors. Furthermore, whether the aroma characteristics of Lingtou Dancong oolong tea are affected by the environmental conditions at different altitudes is unknown. In this study, the aromas in Lingtou Dancong oolong tea were extracted and analyzed by stir-bar sorptive extraction (SBSE) combined with gas chromatography-olfactometry (GC-O) and GC-mass spectrometry (GC-MS), and the aroma profiles of tea plants grown at different altitudes were compared. We detected 59 odor compounds in Lingtou Dancong oolong tea. Eight compounds with honey and floral odors were identified as key components on the basis of GC-O, GC-MS, odor activity value, and flavor dilution analyses. Differences in the contents of precursor geranyl diphosphate and transcript levels of structural genes were found to be responsible for the differential accumulation of linalool and hotrienol among plants grown at different altitudes. This is the first report on the aroma characteristics and key contributors of Lingtou Dancong oolong tea and their differences, as affected by altitude. These results provide details of the chemical basis of the aroma quality of Lingtou Dancong oolong tea. [ABSTRACT FROM AUTHOR]

Jasmonic acid (JA) is reportedly involved in the interaction between insects and the vegetative parts of horticultural crops; less attention has, however, been paid to its involvement in the interaction between insects and the floral parts of horticultural crops. Previously, we investigated the allene oxide synthase 2 (AOS2) gene that was found to be the only JA synthesis gene upregulated in tea (Camellia sinensis) flowers exposed to insect (Thrips hawaiiensis (Morgan)) attacks. In our present study, transient expression analysis in Nicotiana benthamiana plants confirmed that CsAOS2 functioned in JA synthesis and was located in the chloroplast membrane. In contrast to tea leaves, the metabolite profiles of tea flowers were not significantly affected by 10 h JA (2.5 mM) treatment as determined using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry, and gas chromatography-mass spectrometry. Moreover, JA treatment did not significantly influence ethylene formation in tea flowers. These results suggest that JA in tea flowers may have different functions from JA in tea leaves and other flowers. [ABSTRACT FROM AUTHOR]

The global tea (Camellia sinensis L.) output has been in decline despite the continued increases in global tea consumption amount and cultivation area. Application of potassium (K) fertilizer is a common way to enhance tea yield and quality, given the widespread deficiency of soil-available K in tea plantations. However, the specific effects of K fertilizer application upon tea yield and quality and its differential effects among varied K fertilizer application amount, soil-available K amount and tea types remain unknown. In this study, 518 pairwise comparisons between tea productivity after non-application and application of K fertilizers were obtained through a literature review, and then analyzed. The results showed that K application had a significant positive effect on tea yield and overall quality, enhancing the amount of tea yield, the content of amino acid, tea polyphenol, water extract, and catechin by 7.83 %, 7.84 %, 26.79 %, 1.57 % and 6.47 %, respectively. Furthermore, a K application rate of 90–120 kg ha−1 maximized the tea yield and quality. However, K application showed varied effects on tea yield and quality in soils with different available K levels. In terms of tea types, the yield and quality of black and green tea were enhanced under K application. The results of a mixed-effects model indicated that the main factors affecting tea quality were the amount of K fertilizer applied and the soil-available K content, whereas the variation in tea yield results mainly from the tea types. Therefore, to develop high-quality tea plantations and address the contradiction between low tea yield and high tea consumption, efforts should be made to enhance the soil-available K content by optimizing the amount of K applied on tea plantations. [Display omitted] • K application significantly increases tea yield and overall quality. • K application rate of 90–120 kg ha−1 generally maximize tea yield and quality. • Tea quality mainly depends on K fertilizer amount and soil-available K content. • The variation in tea yield mainly results from the tea types. • Optimizing potassium application is crucial for tea quality improvement. [ABSTRACT FROM AUTHOR]