NbJAZ3 is required for jasmonate-meditated glandular trichome development in Nicotiana benthamiana.

Exogenous methyl jasmonate (MeJA) treatment induces glandular trichome development in Nicotiana benthamiana, but the function of JAZ proteins, acting as core repressors, and their downstream genes have not been clearly shown in plants. Here, a bioinformatics analysis of 71 JAZ genes from tobacco, Arabidopsis thaliana, and tomato was carried out and shown to share highly conserved domains. Then, the expression profile of 17 NbJAZs in different tissues was analyzed, and NbJAZ3 was highly expressed in trichome. Through transgenic technology, we demonstrated that the glandular trichome density of NbJAZ3-overexpression lines significantly decreased with lower expression levels of NbWo, NbCycB2, and NbMIXTA. In contrast, the trichome density of NbJAZ3 RNAi lines slightly increased with higher expression level of NbWo. Given the negative protein feedback regulation relationship between NbCycB2 and NbWo, we verified that MeJA induced NbWo expression. NbWo was a direct target gene of NbJAZ3 and further demonstrated that NbJAZ3 inhibited the transcriptional activation of NbCycB2 by NbWo. Together, our findings outline a novel JA-meditated glandular trichome development model consisting of the NbJAZ3-NbWo-NbCycB2 axis.

Rapid expansion of coastal aquaculture ponds in Southeast Asia: Patterns, drivers and impacts.

Aquaculture pond is one of the most important land use types and a main income source in coastal zones in Southeast Asia. However, the fast expansion of aquaculture ponds threatens coastal ecosystems - an issue that Sustainable Development Goals (SDGs)14 seeks to address. Investigating expansion patterns is essential for exploring the drivers and understanding its impacts, and thus the focus of the sustainable management of aquaculture. This study aims to assess the spatio-temporal expansion patterns of aquaculture ponds with multitemporal remote sensing images and geographic information system in the coastal zone of Southeast Asia over a 25-year period (1990-2015), to understanding how globalization and economic policies may have contributed to such changes. The results show that, in 2015, total area of coastal aquaculture ponds was about 23,245 km2, and 79% of coastal aquaculture ponds distributed within 15 km from the coastline. And the amount has expanded about 2.6 times in the past 25 years. Vietnam has the largest area of aquaculture in 2015 and the highest annual increasing rate, accounting for 40.28% and 298.5 km2/y, followed by Indonesia (31.50% and 156.8 km2/y), Thailand (10.79% and 64.8 km2/y), Myanmar (8.76% and 61.1 km2/y). The expansion pattern of aquaculture ponds in the region altered from outlying to edge-expansion from the year of 2000. The main drivers of rapid expansion lie to the intensified local fisher policies as a result of economic globalization. While development of aquaculture has enhanced family income, it has also led to significant reduction of mangrove and coastal water pollution (eutrophication). With the prevailing antagonism between aquaculture expansion and ecosystem conversion, our research call for the local government's attention to sustainable management of aquaculture. This will be the key to reduce food safety risk and simultaneously prevent inevitable damages to coastal ecosystems, as stipulated by SDGs 2 and 14.

NbCycB2 represses Nbwo activity via a negative feedback loop in tobacco trichome development.

The transcription factor Woolly (Wo) and its downstream gene CycB2 have been shown to regulate trichome development in tomato (Solanum lycopersicum). It has been demonstrated that only the gain-of-function allele of Slwo (SlWoV, the Slwo woolly motif mutant allele) can increase the trichome density; however, it remains unclear why the two alleles function differently in trichome development. In this study, we used Nicotiana benthamiana as a model and cloned the homologues of Slwo and SlCycB2 (named Nbwo and NbCycB2). We also constructed a Nbwo gain-of-function allele with the same mutation site as SlWoV (named NbWoV). We found that both Nbwo and NbWoV directly regulate NbCycB2 and their own expression by binding to the promoter of NbCycB2 and their own genomic sequences. As form of a feedback regulation, NbCycB2 negatively regulates trichome formation by repressing Nbwo activity at the protein level. We also found that mutations in the Nbwo woolly motif can prevent repression of NbWoV by NbCycB2, which results in a significant increase in the amount of active Nbwo proteins and in increases in trichome density and the number of branches. Our results reveal a novel reciprocal regulation mechanism between NbCycB2 and Nbwo during trichome formation in N. benthamiana.

Fine Mapping of a Gene (ER4.1) that Causes Epidermal Reticulation of Tomato Fruit and Characterization of the Associated Transcriptome.

The hydrophobic cuticle that covers the surface of tomato (Solanum lycopersicum) fruit plays key roles in development and protection against biotic and abiotic stresses, including water loss, mechanical damage, UV radiation, pathogens, and pests. However, many details of the genes and regulatory mechanisms involved in cuticle biosynthesis in fleshy fruits are not well understood. In this study, we describe a novel tomato fruit phenotype, characterized by epidermal reticulation (ER) of green fruit and a higher water loss rate than wild type (WT) fruit. The ER phenotype is controlled by a single gene, ER4.1, derived from an introgressed chromosomal segment from the wild tomato species S. pennellii (LA0716). We performed fine mapping of the single dominant gene to an ~300 kb region and identified Solyc04g082540, Solyc04g082950, Solyc04g082630, and Solyc04g082910as potential candidate genes for the ER4.1 locus, based on comparative RNA-seq analysis of ER and WT fruit peels. In addition, the transcriptome analysis revealed that the expression levels of genes involved in cutin, wax and flavonoid biosynthesis were altered in the ER fruit compared with WT. This study provides new insights into the regulatory mechanisms and metabolism of the fruit cuticle.