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3D detection task plays a crucial role in the perception system of intelligent vehicles. LiDAR-based 3D detectors perform well on particular autonomous driving benchmarks, but may poorly generalize to other domains. Existing 3D domain adaptive detection methods usually require annotation-related statistics or continuous refinement of pseudo-labels. The former is not always feasible for practical applications, while the latter lacks sufficient accurate supervision. In this work, we propose a novel unsupervised domain adaptive framework, namely Adaptation Via Proxy (AVP), that explicitly leverages cross-domain relationships to generate adequate high-quality samples, thus mitigating domain shifts for existing LiDAR-based 3D detectors. Specifically, we first train the detector on source domain with the curriculum example mining (CEM) strategy to enhance its generalization capability. Then, we integrate the profitable instance knowledge from the source domain with the contextual information from the target domain, to construct the instance-aware proxy, which is a data collection with diverse training scenes and stronger supervision. Finally, we fine-tune the pre-trained detector on the proxy data for further optimizing the detector to overcome domain gaps. To build the instance-aware proxy, two components are proposed, i.e., the multi-view multi-scale aggregation (MMA) method for producing high-quality pseudo-labels, and the hybrid instance augmentation (HIA) technique for integrating the knowledge from source annotations to enhance supervision. Note that AVP is architecture-agnostic thus it can be easily injected with any LiDAR-based 3D detectors. Extensive experiments on Waymo, nuScenes, KITTI and Lyft demonstrate the superiority of the proposed method over the state-of-the-art approaches for different adaptation scenarios.

Horticultural crops comprising fruit, vegetable, ornamental, beverage, medicinal and aromatic plants play essential roles in food security and human health, as well as landscaping. With the advances of sequencing technologies, genomes for hundreds of horticultural crops have been deciphered in recent years, providing a basis for understanding gene functions and regulatory networks and for the improvement of horticultural crops. However, these valuable genomic data are scattered in warehouses with various complex searching and displaying strategies, which increases learning and usage costs and makes comparative and functional genomic analyses across different horticultural crops very challenging. To this end, we have developed a lightweight universal search engine, HortGenome Search Engine (HSE; http://hort.moilab.net), which allows for the querying of genes, functional annotations, protein domains, homologs, and other gene-related functional information of more than 500 horticultural crops. In addition, four commonly used tools, including ‘BLAST’, ‘Batch Query’, ‘Enrichment analysis’, and ‘Synteny Viewer’ have been developed for efficient mining and analysis of these genomic data.

Improving soil conditions has been an increasingly important issue in degraded hilly areas; however, the effects of plant manure on soil nutrient and plant dry matter accumulation are poorly understood. We studied the effects of alfalfa powder, decomposed chicken manure and drought in a nonplanted group (NPG) and planted walnut group (PG) soil to explore the regulatory mechanisms of plant growth and dry matter accumulation in response to soil nutrients in hilly areas. Alfalfa fertilizer increased the soil water content and organic nutrient content, and drought resulted in a high carbon to nitrogen ratio and carbon to phosphorus ratio in NPG and PG soil. In addition, fertilization changed the available nutrient content of the soil in the nonirrigated NPG and PG. Alfalfa fertilizer altered the soil micro‐element contents and leaf mineral nutrient contents, promoted the net photosynthetic rate and relative water content, and inhibited the transpiration rate, resulting in high water use efficiency in leaves. Moreover, the coupling effect of soil organic matter and soil water content affected the correlations between the organic composition and mineral nutrients and maintained leaf mineral element contents as well as the net photosynthetic rate and water use efficiency, resulting in dry matter accumulation in the leaves, shoots and roots. This study highlights that plant manure can improve soil properties and the accumulation of plant dry matter in hilly areas. Core IdeasAlfalfa powder enhanced soil fertility in mountainous/hilly areas.Alfalfa powder improved leaf nutrient contents, leaf photosynthesis and water use efficiency (WUE) in drought.Soil environmental factors were correlated with plant growth and dry matter accumulation. Alfalfa powder enhanced soil fertility in mountainous/hilly areas. Alfalfa powder improved leaf nutrient contents, leaf photosynthesis and water use efficiency (WUE) in drought. Soil environmental factors were correlated with plant growth and dry matter accumulation.

Pear (Pyrus pyrifolia(Burm. f.) cv. Nak.) is cultivated worldwide, with China ranking as the top producer of Asian pear. Pear trees often waste a lot of nutrients during the growing process, due to the large number of flowers on the trees. Traditional thinning methods to reduce flower number are often laborious and time-consuming and affect fruit quality. Here, we investigated the use of plant-derived nutrient solution (PDNS), a liquid organic fertilizer that is made from naturally fallen tree fruit, as a thinning agent. PDNS was sprayed onto two pear cultivars, ‘Whangkeumbae’ and ‘Hosui’ during bud, flower and fruit stage. We observed that the thinning effect of PDNS was significantly greater than that of widely used chemical thinning agents and that PDNS can promote pear tree vegetative growth and fruit quality. The work described in this report lays a foundation for developing protocols using environmentally benign thinning agents in organic fruit production.

It has been demonstrated that the use of organic materials in fruit orchards can effectively increase soil fertility, fruit production and fruit quality. Insect and disease damage, crop thinning, natural drop cause abscission and abscised parts are a source of organic additives for orchard production. In this study, we developed a fermented nutrient solution composed of young apple fruits, brown sugar, a fermenting agent and water. Diluted solutions (1:100 and 1:200) of this nutrient solution were sprayed on 2-year-old and 12-year-old apple (Malus domestica(Borkh.) ‘Fuji’) trees. The results showed that foliar spraying of the fermentation solutions significantly improved tree height, trunk circumference, shoot growth and leaf area of young apple trees, and increased the fruit weight, shape index, firmness, soluble solid content, volatile compound content and vitamin C content of adult apple trees, as compared to the control treatment. The effects of the 1:200 diluted nutrient solution were significantly greater than those of the 1:100 diluted nutrient solution. Foliar spray of a nutrient solution derived from young apple fruit promoted vegetative growth and fruit quality.

ABSTRACTCrabapple (Malusspp.) trees constitute an important worldwide germplasm resource with high ornamental, agricultural, and nutritional value. The content and composition of flavonoids in fruits are major determinants of the colouration and nutritional value of fruits; however, the mechanisms of red colouration and flavonoid biosynthesis in crabapple fruits are not yet fully understood. Two crabapple cultivars, the ever-red fruited ‘Royalty’ and the green-to-red fruited ‘Flame’, were studied during fruit development. In both cultivars, our results showed that the McMYB10transcript level is associated with fruit colouration and anthocyanin and quercetin contents in fruit peel during fruit development. Shading treatments affected fruit colouration by regulating the expression levels of McMYB10in ‘Royalty’. Transient over-expression of McMYB10in crabapple fruit promoted transcription of some flavonoid biosynthetic genes and induced anthocyanin and quercetin accumulation and red colouration in crabapple fruits. Our study indicates that McMYB10 is a key regulator of anthocyanin and quercetin biosynthesis during crabapple fruit development.

The rare ever-red crabapple (Malusspp.) leaves have importantly ornamental and medicinal traits, and their coloration is regulated by light conditions. However, little is known about the molecular mechanism of the red color formation via anthocyanin biosynthesis mediated by upstream regulators of light signaling under different light conditions. We selected the ever-red leaf cultivar, M.cv.‘Royalty,’ to investigate the expression profile of various factors under dark conditions. The factors studied include the photoreceptors McphyAand McphyB, the ubiquitin E3 ligase McCOP1, the transcription factor McMYB10, the MBW complex, the main structural genes in anthocyanin biosynthesis, and the photomorphogenesis transcription factors McbZIPand McHY5. Our results indicated that under dark conditions McCOP1expression was up-regulated, while the expression of other factors studied was down-regulated, leading to decreased expression of the structural genes involved in anthocyanin biosynthesis and reduction in anthocyanin content. Interestingly, when McCOP1was silenced in the leaves, the expression of McMYB10, McbHLH, McWD40, McbZIP, and McHY5was markedly up-regulated, resulting in the up-regulation of the structural genes including McF3H, McFLS, McDFR, and McUFGTand the subsequent accumulation of anthocyanins compared with leaves treated with empty vector. These data demonstrate that darkness negatively regulates the coloration of the ever-red leaves by regulating McCOP1expression, further inhibiting the expression of McMYB10and the structural genes in anthocyanin biosynthesis. These results may provide important insight into the breeding of color-leafed plants.

Low temperature can affect the growth and development of plants through changes in DNA demethylation patterns. Another known effect of low temperature is the accumulation of anthocyanin pigments. However, it is not known whether the two phenomena are linked, specifically whether DNA demethylation participates in anthocyanin accumulation in response to low-temperature stress. The ROS1gene is involved in plant DNA demethylation and influences methylation levels in response to low-temperature stress. In this study, using RNA sequencing, we detected the transcription levels of MdROS1, as well as those of anthocyanin biosynthesis-related genes, correlate with the anthocyanin content in apple (Malus domestica), at low temperature. Genomic bisulfite sequencing showed that the methylation levels of the promoters of the anthocyanin-related genes MdCHS, MdCHI, MdF3′H, MdANS, MdUFGT, and MdMYB10decreased in apple leaves after low-temperature treatment. Similar expression and methylation results were found in apple fruit. Transiently silencing MdROS1in the leaves and fruit of apple cultivars inhibited the accumulation of anthocyanins and led to decreased expression of anthocyanin biosynthetic genes, and the opposite results were detected in MdROS1-overexpressing leaves and fruit. A promoter binding assay showed that the conserved RRD-DME domains of MdROS1 bind directly to the promoters of MdF3′Hand MdUFGT. Taken together, these results suggest that ROS1 affects the anthocyanin biosynthetic pathway by decreasing the methylation level of anthocyanin-related gene promoters, thereby increasing their expression and increasing anthocyanin accumulation.

Temperature changes affect apple development and production. Phenylpropanoid metabolism and hormone signaling play a crucial role in regulating apple growth and development in response to temperature changes. Here, we found that McMYB4is induced by treatment at 28 °C and 18 °C, and McMYB4overexpression results in flavonol and lignin accumulation in apple leaves. Yeast one-hybrid (Y1H) assays and electrophoretic mobility shift assays (EMSAs) further revealed that McMYB4 targets the promoters of the flavonol biosynthesis genes CHSand FLSand the lignin biosynthesis genes CADand F5H. McMYB4expression resulted in higher levels of flavonol and lignin biosynthesis in apple during growth at 28 °C and 18 °C than during growth at 23 °C. At 28 °C and 18 °C, McMYB4 also binds to the AUX/ARFand BRI/BINpromoters to activate gene expression, resulting in acceleration of the auxin and brassinolide signaling pathways. Taken together, our results demonstrate that McMYB4 promotes flavonol biosynthesis and brassinolide signaling, which decreases ROS contents to improve plant resistance and promotes lignin biosynthesis and auxin signaling to regulate plant growth. This study suggests that McMYB4 participates in the abiotic resistance and growth of apple in response to temperature changes by regulating phenylpropanoid metabolism and hormone signaling.

Flavonols are polyphenolic compounds that play important roles in plant stress resistance and development. They are also valuable components of the human diet. The Maluscrabapple cultivar ‘Flame’ provides an excellent model for studying flavonol biosynthesis due to the high flavonol content of its fruit peel. To obtain a more detailed understanding of the flavonol regulatory network involved in fruit development, the transcriptomes of the fruit of the Maluscv. ‘Flame’ from five continuous developmental stages were analyzed using RNA sequencing. A flavonol-related gene module was identified through weighted gene coexpression network analysis (WGCNA), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that phytohormones are involved in regulating flavonol biosynthesis during fruit development. A putative transcription factor, MdMYB8, was selected for further study through hub gene correlation network analysis and yeast one-hybrid assays. Stable overexpression or RNAi knockdown of MdMYB8in transgenic ‘Orin’ apple calli resulted in a higher or lower flavonol content, respectively, suggesting that MdMYB8is a regulator of flavonol biosynthesis. This transcriptome analysis provides valuable data for future studies of flavonol synthesis and regulation.