Orographic evolution of northern Tibet shaped vegetation and plant diversity in eastern Asia

The growth of the Tibetan Plateau throughout the past 66 million years has profoundly affected the Asian climate, but how this unparalleled orogenesis might have driven vegetation and plant diversity changes in eastern Asia is poorly understood. We approach this question by integrating modeling results and fossil data. We show that growth of north and northeastern Tibet affects vegetation and, crucially, plant diversity in eastern Asia by altering the monsoon system. This northern Tibetan orographic change induces a precipitation increase, especially in the dry (winter) season, resulting in a transition from deciduous broadleaf vegetation to evergreen broadleaf vegetation and plant diversity increases across southeastern Asia. Further quantifying the complexity of Tibetan orographic change is critical for understanding the finer details of Asian vegetation and plant diversity evolution.

Ethnobotanical study on wild edible plants used by three trans-boundary ethnic groups in Jiangcheng County, Pu'er, Southwest China

BACKGROUND

Dai, Hani, and Yao people, in the trans-boundary region between China, Laos, and Vietnam, have gathered plentiful traditional knowledge about wild edible plants during their long history of understanding and using natural resources. The ecologically rich environment and the multi-ethnic integration provide a valuable foundation and driving force for high biodiversity and cultural diversity in this region. However, little study has uncovered this unique and attractive culture to the world.

METHODS

We conducted ethnobotanical survey in 20 villages of Jiangcheng County from 2016 to 2020. Altogether 109 local Dai, Hani, and Yao people were interviewed, and their traditional knowledge about wild edible plants was recorded. Voucher specimens were identified by the authors and deposited in the herbarium of Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences (HITBC). The use value was used as a quantitative index to evaluate the consumption frequency and relative importance of the wild edible plants. The Jaccard index was calculated to assess the usage similarity of different areas. The relationship of age and recognized wild edible plants by different ethnic people was performed by R.

RESULTS

A total of 211 wild edible plants, belonging to 71 families and 151 genera, were recorded. These plants were consumed as wild edible vegetables, seasonal fruits, salads, spices, sour condiments, tonic soups, tea substitutes, liquor brewing, or dyeing materials. The use value (UV), current cultivation, market availability, and the quantitative traditional knowledge inheritance situation of these wild edible plants among different generations, were analyzed. Based on the data from the threatened species list of China's higher plants and the IUCN Red List, the food plant list for Asia Elephant, the Subject Database of China Plant, and the calculated UV score, the top 30 most important wild edible plants were selected for further cultivation in some local villages.

CONCLUSION

Traditional knowledge of wild edible plants, owned by Dai, Hani, and Yao people in Jiangcheng County, is rich but at risk of being lost among the young generation. Diversified cultivation of wild edible plants by the local communities could be a solution for the sustainable use of natural resources and to conserve the endangered species in this trans-boundary region.

Transcriptome analysis of two inflorescence branching mutants reveals cytokinin is an important regulator in controlling inflorescence architecture in the woody plant Jatropha curcas

BACKGROUND

In higher plants, inflorescence architecture is an important agronomic trait directly determining seed yield. However, little information is available on the regulatory mechanism of inflorescence development in perennial woody plants. Based on two inflorescence branching mutants, we investigated the transcriptome differences in inflorescence buds between two mutants and wild-type (WT) plants by RNA-Seq to identify the genes and regulatory networks controlling inflorescence architecture in Jatropha curcas L., a perennial woody plant belonging to Euphorbiaceae.

RESULTS

Two inflorescence branching mutants were identified in germplasm collection of Jatropha. The duo xiao hua (dxh) mutant has a seven-order branch inflorescence, and the gynoecy (g) mutant has a three-order branch inflorescence, while WT Jatropha has predominantly four-order branch inflorescence, occasionally the three- or five-order branch inflorescences in fields. Using weighted gene correlation network analysis (WGCNA), we identified several hub genes involved in the cytokinin metabolic pathway from modules highly associated with inflorescence phenotypes. Among them, Jatropha ADENOSINE KINASE 2 (JcADK2), ADENINE PHOSPHORIBOSYL TRANSFERASE 1 (JcAPT1), CYTOKININ OXIDASE 3 (JcCKX3), ISOPENTENYLTRANSFERASE 5 (JcIPT5), LONELY GUY 3 (JcLOG3) and JcLOG5 may participate in cytokinin metabolic pathway in Jatropha. Consistently, exogenous application of cytokinin (6-benzyladenine, 6-BA) on inflorescence buds induced high-branch inflorescence phenotype in both low-branch inflorescence mutant (g) and WT plants. These results suggested that cytokinin is an important regulator in controlling inflorescence branching in Jatropha. In addition, comparative transcriptome analysis showed that Arabidopsis homologous genes Jatropha AGAMOUS-LIKE 6 (JcAGL6), JcAGL24, FRUITFUL (JcFUL), LEAFY (JcLFY), SEPALLATAs (JcSEPs), TERMINAL FLOWER 1 (JcTFL1), and WUSCHEL-RELATED HOMEOBOX 3 (JcWOX3), were differentially expressed in inflorescence buds between dxh and g mutants and WT plants, indicating that they may participate in inflorescence development in Jatropha. The expression of JcTFL1 was downregulated, while the expression of JcLFY and JcAP1 were upregulated in inflorescences in low-branch g mutant.

CONCLUSIONS

Cytokinin is an important regulator in controlling inflorescence branching in Jatropha. The regulation of inflorescence architecture by the genes involved in floral development, including TFL1, LFY and AP1, may be conservative in Jatropha and Arabidopsis. Our results provide helpful information for elucidating the regulatory mechanism of inflorescence architecture in Jatropha.