Monoterpene synthases contribute to the volatile production in tana (Zanthoxylum ailanthoides) through indigenous cultivation practices.

Tana (Zanthoxylum ailanthoides), a perennial deciduous species in the Rutaceae family, possesses leaves with a unique fragrance that indigenous peoples incorporate into their traditional cuisine. In Kalibuan, the cultivated tana trees were pruned repeatedly to maintain a shorter height, which led to the growth of new leaves that were spicier and pricklier. Tana leaves contain a range of volatile terpenoids, and the pungent aroma may arise from the presence of monoterpenoids. To gain insight into the biosynthetic pathway, five candidate monoterpene synthase genes were cloned and characterized using a purified recombinant protein assay. The main product of Za_mTPS1, Za_mTPS2, and Za_mTPS5 is sabinene, geraniol, and (E)-ß-ocimene, respectively. The main product of Za_mTPS3 and Za_mTPS4 is linalool. Real-time PCR analysis revealed that Za_mTPS1 and Za_mTPS5 are expressed at higher levels in prickly leaves of cultivated tana, suggesting that they may contribute to the distinctive aroma of this plant.

Biogeography and Ecological Differentiation of Pseudasphondylia gall midges (Diptera: Cecidomyiidae) Distributed in Taiwan and Japan, with Description of a New Species P. kiwiphila sp. nov. and the Southernmost Record of P. elaeocarpi.

Pseudasphondylia species (Diptera: Cecidomyiidae) are known to induce fruit galls on Actinidia rufa (Siebold & Zucc.) Planch. ex Miq. and finger-like leaf galls on Elaeocarpus sylvestris (Lour.) Poir. in Taiwan, but their taxonomic positions remain undetermined. Based on gall morphology and host plants, they were supposed to be the same or allied species of known Japanese congeners, i.e., P. matatabi Yuasa & Kumazawa inducing flower-bud galls on Actinidia polygama (Sieb. et Zucc.) Maxim and P. elaeocarpi Tokuda & Yukawa inducing finger-like leaf galls on E. sylvestris. Species identifications of these Taiwanese species provide us an opportunity to study biogeographical aspects and transition of ecological features in these Pseudasphondylia species distributed in East Asian Arc. Morphological comparisons and species delimitation by molecular analysis indicated that the cecidomyiid on the fruit of A. rufa is distinct from P. matatabi and thus it is described as a species new to science, P. kiwiphila sp. nov. Lin, Tokuda, & Yang. The leaf galler on E. sylvestris was identical to P. elaeocarpi, whose southernmost distribution range extended to Taiwan, a new record of its distribution. COI-based phylogenetic tree (Bayesian inference and IQ tree) of Pseudasphondylia suggested that leaf galling habitat and univoltine life history are ancestral, whereas fruit or flower-bud galling and multivoltine life history are derived. In addition, the monophyletic Actinidia-associated species lineage is sistered to the clade including the remaining Japanese fruit and flower-bud gallers, suggesting that Pseudasphondylia has colonized on the host genus Actinidia once and later speciated on different plant species of the host genus. As a biogeographical aspect of P. elaeocarpi, 2.7% of the COI distance between Japanese and Taiwanese individuals indicates that they have diverged around 1.2 mya, which corresponds to the last but second separation of Taiwan and Japan in the Pleistocene. As for Actinidia-associated Pseudasphondylia species, the two valid species are allopatric and have distinct areas of origin, suggesting they may have speciated allopatrically. Nevertheless, there is still the possibility of ecological speciation due to the following reasons: (1) Host species (and varieties) and unidentified congener of Actinidia-associated Pseudasphondylia are occurring China, revealing potential occurrence of these gall midges. (2) The divergence time (2.2-2.9 mya) of the two known species corresponds to the late Pliocene to Pleistocene, when China, Taiwan, and Japan were part of the East Asian continent. During this period, their host species were sympatric in southeast China. (3) The host of two named Actinidia-associated Pseudasphondylia species each belong to different plant groups with distinct fruit features. These presume that the speciation might have been caused via sympatric host shift.

Sesquiterpene Synthases of Zanthoxylum ailanthoides: Sources of Unique Aromas of a Folklore Plant in Taiwan.

Zanthoxylum ailanthoides is a traditional spice crop in Taiwan with unique smells and tastes that differ between prickly (young) and nonprickly (mature) leaves. Different volatile terpenes between prickly young and nonprickly mature leaves were identified and considered to be one of the sources of their aromas. A transcriptome database was established to explore the biosynthesis of these compounds, and candidate terpene synthase genes were identified. The functions of these synthases were investigated using recombinant protein reactions in both purification and coexpression assays. ZaTPS1, ZaTPS2, and ZaTPS3 are germacrene D synthases, with different amino acid sequences. The main products of ZaTPS4 are trans-α-bergamotene and (E)-ß-farnesene, whereas ZaTPS5 forms multiple products, and ZaTPS6 produces ß-caryophyllene. ZaTPS7 forms monoterpene (E)-ß-ocimene and sesquiterpene (E,E)-α-farnesene. Reverse transcription PCR of ZaTPS gene expression in young and mature leaves revealed that ZaTPS1 was responsible for the mellow aroma in mature leaves. The expression of ZaTPS6 suggested that it plays a role in the background aromas of both types of leaves. Our findings deepened the understanding of the volatile compounds of Z. ailanthoides and revealed the source of its unique aromas by clarifying the biosynthesis of these compounds.

Flower-visiting insects of genus Melastoma (Myrtales: Melastomataceae) at the Fushan Botanical Garden, Taiwan.

BACKGROUND: We investigated the diversity and behaviour of insects that visit flowers of four native Melastoma (Family Melastomataceae) species of Taiwan and a horticultural hybrid Melastoma species at the Fushan Botanical Garden, Taiwan biweekly from May to August 2020. Visits of flower-visiting insects were classified into seven behavioural categories, based on the insects' behaviour and positions on the flower. The data are further assigned into four insect-flower interactions, namely pollination, herbivory, commensalism and neutralism. Our goal is to provide baseline data of insect-plant interactions of Melastoma, which is a common, but understudied plant genus in the country. NEW INFORMATION: A total of 1,289 visits to flowers were recorded by at least 63 insect morphospecies belonging to seven orders. The number of insect species recorded per Melastoma species ranged from 9 to 39. Visiting, sonication and passing were the three most frequently recorded types of behaviour, collectively accounting for 90.2% (n = 1,240) of the total observations. Pollination was the most dominant insect-flower interaction, accounting for 70.2% of the total observations, followed by neutralism (20.0%), herbivory (6.3%) and commensalism (3.5%). Sweat bees of the genera Lasioglossum and Maculonomia (Hymenoptera: Halictidae) are considered key pollinators to Melastoma species in Fushan Botanical Garden, based on their high number of visits and sonication behaviour. Our study provides the first list of insects that visit the flowers of all Taiwan's known Melastoma species and description of their interactions with the plants.

Trioza turouguei sp. nov. (Hemiptera, Psylloidea, Triozidae), a new psyllid species from Taiwan inducing pea-shaped stem galls on Cinnamomum osmophloeum (Lauraceae), with notes on its galling biology.

Trioza turouguei sp. nov., a new species of jumping plant lice (Hemiptera, Triozidae) from Taiwan, is described and illustrated based on adults and immatures. The latter induce pea-shaped galls on the stems of Cinnamomum osmophloeum Kaneh. (Lauraceae). The gall phenology of the new species is described. A list of species of Triozidae associated with Cinnamomum in the Old World is provided. The following nomenclatorial acts are proposed: Trioza inflata Li, 1992 = Trioza xiangicamphorae Li, 1992, syn. nov.; Siphonaleyrodes formosanus Takahashi, 1932, stat. rev., is removed from synonymy with Trioza cinnamomi (Boselli, 1931).