Global analysis of seed transcriptomes reveals a novel PLATZ regulator for seed size and weight control in soybean.

Seed size and weight are important factors that influence soybean yield. Combining the weighted gene co-expression network analysis (WGCNA) of 45 soybean accessions and gene dynamic changes in seeds at seven developmental stages, we identified candidate genes that may control the seed size/weight. Among these, a PLATZ-type regulator overlapping with 10 seed weight QTLs was further investigated. This zinc-finger transcriptional regulator, named as GmPLATZ, is required for the promotion of seed size and weight in soybean. The GmPLATZ may exert its functions through direct binding to the promoters and activation of the expression of cyclin genes and GmGA20OX for cell proliferation. Overexpression of the GmGA20OX enhanced seed size/weight in soybean. We further found that the GmPLATZ binds to a 32-bp sequence containing a core palindromic element AATGCGCATT. Spacing of the flanking sequences beyond the core element facilitated GmPLATZ binding. An elite haplotype Hap3 was also identified to have higher promoter activity and correlated with higher gene expression and higher seed weight. Orthologues of the GmPLATZ from rice and Arabidopsis play similar roles in seeds. Our study reveals a novel module of GmPLATZ-GmGA20OX/cyclins in regulating seed size and weight and provides valuable targets for breeding of crops with desirable agronomic traits.

A transcriptional regulatory module controls lipid accumulation in soybean.

Soybean (Glycine max) is one of the most important oilseed crops. However, the regulatory mechanism that governs the process of oil accumulation in soybean remains poorly understood. In this study, GmZF392, a tandem CCCH zinc finger (TZF) protein which was identified in our previous RNA-seq analysis of seed-preferred transcription factors, was found to function as a positive regulator of lipid production. GmZF392 promotes seed oil accumulation in both transgenic Arabidopsis and stable transgenic soybean plants by binding to a bipartite cis-element, containing TG- and TA-rich sequences, in promoter regions, activating the expression of genes in the lipid biosynthesis pathway. GmZF392 physically interacts with GmZF351, our previously identified transcriptional regulator of lipid biosynthesis, to synergistically promote downstream gene expression. Both GmZF392 and GmZF351 are further upregulated by GmNFYA, another transcription factor involved in lipid biosynthesis, directly (in the former case) and indirectly (in the latter case). Promoter sequence diversity analysis showed that the GmZF392 promoter may have been selected at the origin of the Glycine genus and further mildly selected during domestication from wild soybeans to cultivated soybeans. Our study reveals a regulatory module containing three transcription factors in the lipid biosynthesis pathway, and manipulation of the module may improve oil production in soybean and other oilseed crops.

Evolutionarily conserved function of the sacred lotus (Nelumbo nucifera Gaertn.) CER2-LIKE family in very-long-chain fatty acid elongation.

MAIN CONCLUSION: Identification of NnCER2 and NnCER2-LIKE from Nelumbo nucifera, which are required for the very-long-chain fatty acid elongation, provides new evidence that CER2 proteins are evolutionarily conserved across the eudicots. CER2-LIKE family proteins have been described as core components of the fatty acid elongase complex in Arabidopsis, maize, and rice, having specific function in synthesis of the C30 to C34 fatty acyl-CoA precursors of cuticular waxes. Little is known about the functional conservation in this gene family across species. In this study, two CER2-LIKE family proteins, NnCER2 and NnCER2-LIKE, were characterized from sacred lotus (Nelumbo nucifera), which is an ancient basal eudicot. The transcriptional expression of NnCER2 and NnCER2-LIKE was found in floating leaf blades, emergent petioles and vertical leaves, petals, and anthers. The NnCER2 and NnCER2-LIKE proteins were localized to the endoplasmic reticulum and nucleus. Overexpressing NnCER2 and NnCER2-LIKE in Arabidopsis led to alteration of cuticle wax structure in inflorescence stems, and this was associated with elevated 30, 32, and 34 carbon length wax compounds, and their derivatives. The different substrate specificities of NnCER2 and NnCER2-LIKE were explored using co-expression with AtCER6 in yeast cells. These findings provide clear evidence that the function of CER2 family proteins in producing VLCFAs is highly conserved across the eudicots.

The Acyl Desaturase CER17 Is Involved in Producing Wax Unsaturated Primary Alcohols and Cutin Monomers.

We report n-6 monounsaturated primary alcohols (C26:1, C28:1, and C30:1 homologs) in the cuticular waxes of Arabidopsis (Arabidopsis thaliana) inflorescence stem, a class of wax not previously reported in Arabidopsis. The Arabidopsis cer17 mutant was completely deficient in these monounsaturated alcohols, and CER17 was found to encode a predicted ACYL-COENZYME A DESATURASE LIKE4 (ADS4). Studies of the Arabidopsis cer4 mutant and yeast variously expressing CER4 (a predicted fatty acyl-CoA reductase) with CER17/ADS4, demonstrated CER4's principal role in synthesis of these monounsaturated alcohols. Besides unsaturated alcohol deficiency, cer17 mutants exhibited a thickened and irregular cuticle ultrastructure and increased amounts of cutin monomers. Although unsaturated alcohols were absent throughout the cer17 stem, the mutation's effects on cutin monomers and cuticle ultrastructure were much more severe in distal than basal stems, consistent with observations that the CER17/ADS4 transcript was much more abundant in distal than basal stems. Furthermore, distal but not basal stems of a double mutant deficient for both CER17/ADS4 and LONG-CHAIN ACYL-COA SYNTHETASE1 produced even more cutin monomers and a thicker and more disorganized cuticle ultrastructure and higher cuticle permeability than observed for wild type or either mutant parent, indicating a dramatic genetic interaction on conversion of very long chain acyl-CoA precursors. These results provide evidence that CER17/ADS4 performs n-6 desaturation of very long chain acyl-CoAs in both distal and basal stems and has a major function associated with governing cutin monomer amounts primarily in the distal segments of the inflorescence stem.

Keyframe image processing of semantic 3D point clouds based on deep learning.

With the rapid development of web technologies and the popularity of smartphones, users are uploading and sharing a large number of images every day. Therefore, it is a very important issue nowadays to enable users to discover exactly the information they need in the vast amount of data and to make it possible to integrate their large amount of image material efficiently. However, traditional content-based image retrieval techniques are based on images, and there is a "semantic gap" between this and people's understanding of images. To address this "semantic gap," a keyframe image processing method for 3D point clouds is proposed, and based on this, a U-Net-based binary data stream semantic segmentation network is established for keyframe image processing of 3D point clouds in combination with deep learning techniques.

De novo Assembly and Characterization of the Fruit Transcriptome of Idesia polycarpa Reveals Candidate Genes for Lipid Biosynthesis.

Idesia polycarpa, is a valuable oilseed-producing tree of the Flacourtiaceae family that has the potential to fulfill edible oil production and is also a possible biofuel feedstock. The fruit is unique in that it contains both saturated and unsaturated lipids present in pericarp and seed, respectively. However, triglyceride synthesis and storage in tissues outside of the seeds has been poorly studied in previous researches. To gain insight into the unique properties of I. polycarpa fruit lipid synthesis, biochemical, and transcriptomic approaches were used to compare the lipid accumulation between pericarp and seed of the fruit. Lipid accumulation rates, final lipid content and composition were significantly different between two tissues. Furthermore, we described the annotated transcriptome assembly and differential gene expression analysis generated from the pericarp and seed tissues. The data allowed the identification of distinct candidate genes and reconstruction of lipid pathways, which may explain the differences of oil synthesis between the two tissues. The results may be useful for engineering alternative pathways for lipid production in non-seed or vegetative tissues.