Plant diseases cause significant economic losses and food security in agriculture each year, with the critical path to reducing losses being accurate identification and timely diagnosis of plant diseases. Currently, deep neural networks have been extensively applied in plant disease identification, but such approaches still suffer from low identification accuracy and numerous parameters. Hence, this paper proposes a model combining channel attention and channel pruning called CACPNET, suitable for disease identification of common species. The channel attention mechanism adopts a local cross-channel strategy without dimensionality reduction, which is inserted into a ResNet-18-based model that combines global average pooling with global max pooling to effectively improve the features’ extracting ability of plant leaf diseases. Based on the model’s optimum feature extraction condition, unimportant channels are removed to reduce the model’s parameters and complexity via the L1-norm channel weight and local compression ratio. The accuracy of CACPNET on the public dataset PlantVillage reaches 99.7% and achieves 97.7% on the local peanut leaf disease dataset. Compared with the base ResNet-18 model, the floating point operations (FLOPs) decreased by 30.35%, the parameters by 57.97%, the model size by 57.85%, and the GPU RAM requirements by 8.3%. Additionally, CACPNET outperforms current models considering inference time and throughput, reaching 22.8 ms/frame and 75.5 frames/s, respectively. The results outline that CACPNET is appealing for deployment on edge devices to improve the efficiency of precision agriculture in plant disease detection.

In flowering plants, floral induction signals intersect at the shoot apex to modulate meristem determinacy and growth form. Herein, we reported a snRNA-seq analysis of litchi apical buds at different developmental stages. A total of 41,641 nuclei expressing 21,402 genes were analyzed, revealing 35 cell clusters corresponding to 12 broad populations. We signature genes associated with floral transition and propose a model that profile the key events associated with litchi floral meristem identity by analyzing 567 identified floral meristem cells at single cell resolution. Interestingly, snRNA-seq data indicated that all putative FT and TFL1 genes were not expressed in bud nuclei, but significant expressions of them were detected in bud samples using RT-PCR. Based on the expression patterns and gene silencing results, we highlight the critical role of LcTFL1-2 in inhibiting flowering and propose that LcFT1/LcTFL1-2 expression ratio may determine the success flower transition. And the transport of LcFT1 and LcTFL1-2 mRNA from the leaf to the shoot apical meristem was proposed based on in-situ and dot blot hybridization results. These findings allowed for a more comprehensive understanding of the molecular events that occur during the litchi floral transition, as well as the identification of new regulators.

Recent advances in developmental biology have been made possible by using multi-omic studies at single cell resolution. However, progress in plants has been slowed, owing to the tremendous difficulty in protoplast isolation from most plant tissues and/or oversize protoplasts during flow cytometry purification. Surprisingly, rapid innovations in nucleus research have shed light on plant studies in single cell resolution, which necessitates high quality and efficient nucleus isolation. Herein, we present efficient nuclei isolation protocols from the leaves of ten important plants including Arabidopsis, rice, maize, tomato, soybean, banana, grape, citrus, apple, and litchi. We provide a detailed procedure for nucleus isolation, flow cytometry purification, and absolute nucleus number quantification. The nucleus isolation buffer formula of the ten plants tested was optimized, and the results indicated a high nuclei yield. Microscope observations revealed high purity after flow cytometry sorting, and the DNA and RNA quality extract from isolated nuclei were monitored by using the nuclei in cell division cycle and single nucleus RNA sequencing (snRNA-seq) studies, with detailed procedures provided. The findings indicated that nucleus yield and quality meet the requirements of snRNA-seq, cell division cycle, and likely other omic studies. The protocol outlined here makes it feasible to perform plant omic studies at single cell resolution.

Grafting is a prevalent horticultural technique that enhances crop yields and stress resilience; nevertheless, compatibility issues frequently constrain its efficacy. This research examined the physiological, hormonal, and transcriptional factors regulating compatibility between the litchi (Litchi chinensis Sonn.) cultivars Feizixiao (FZX) and Ziniangxi (ZNX). The anatomical and growth investigations demonstrated significant disparities between compatible (FZX as scion and ZNX as rootstock) and incompatible (ZNX as scion and FZX as rootstock) grafts, with the latter showing reduced levels of indole acetic acid (IAA). Exogenous 1-naphthalene acetic acid (NAA) application markedly improved the graft survival, shoot development, and hormonal synergy, whereas the auxin inhibitor tri-iodobenzoic acid (TIBA) diminished these parameters. The incompatible grafts showed downregulation of auxin transporter genes, including ATP-binding cassette (ABC) transporter, AUXIN1/LIKE AUX1 (AUX/LAX), and PIN-FORMED (PIN) genes, suggesting impaired vascular tissue growth. Metabolomic profiling revealed dynamic interactions between auxin, salicylic acid, and jasmonic acid, with NAA-treated grafts exhibiting enhanced levels of stress-responsive metabolites. Transcriptome sequencing identified differentially expressed genes (DEGs) linked to auxin signaling (ARF, GH3), seven additional phytohormones, secondary metabolism (terpenoids, anthocyanins, and phenylpropanoids), and ABC transporters. Gene ontology and KEGG analyses highlighted the significance of hormone interactions and the biosynthesis of secondary metabolites in successful grafting. qRT-PCR validation substantiated the veracity of the transcriptome data, emphasizing the significance of auxin transport and signaling in effective graft development. This study provides an in-depth review of the molecular and physiological factors influencing litchi grafting. These findings provide critical insights for enhancing graft success rates in agricultural operations via targeted hormonal and genetic approaches.

Although extensively studied in various plants, the roles of aquaporin proteins in litchi remain unclear. In this study, low moisture content was observed in the dormant terminal buds of litchi. Transcriptome analysis revealed that two aquaporin genes, PLASMA MEMBRANE INTRINSIC PROTEIN 1;4 (LcPIP1;4) and LcPIP1;5, could be remarkably inhibited by exogenous ethylene (ETH), which also reduced the moisture content of litchi buds. Quantitative real-time polymerase chain reaction assays indicated that LcPIP1;4 expression was relatively elevated in the dormancy stage of litchi terminal buds. Inhibition of LcPIP1;4 in the buds of litchi during the growth stage delayed the onset of dormancy, resulting in a significantly reduced dormancy rate and increased moisture content. Further study indicated that LcPIP1;4 interacts with LcPIP1;4a, and they are capable of self-interaction. Silencing of LcPIP1;4a in litchi buds resulted in a phenotype consistent with silencing of LcPIP1;4. Additionally, simultaneous silencing of both LcPIP1;4 and LcPIP1;4a resulted in a more severe bud dormancy phenotype. Moreover, LcPIP1;4 was directly upregulated by LcRAP2.4. Silencing of LcRAP2.4 also delayed the onset of dormancy in litchi terminal buds, which is regulated by LcSVP2. ETH treatment at 1000 mg/l significantly downregulated the expression of LcPIP1;4 and LcRAP2.4, but had no significant effect on LcPIP1;4a. In contrast, abscisic acid (ABA) treatment at 200 mg/l significantly upregulated the expression of LcPIP1;4, LcPIP1;4a, and LcRAP2.4. Combined treatment with ETH and ABA exerted a stronger inhibitory effect on the bud break and upregulated LcPIP1;4 and LcRAP2.4 to lower degrees than ABA alone, suggesting that ABA reversed the inhibitory effect of ETH on the expression of LcPIP1;4 and LcRAP2.4. ABA treatment and combined treatment with ETH and ABA effectively reduced the moisture content of the terminal buds. These results demonstrate that LcRAP2.4, LcPIP1;4, and LcPIP1;4a play a vital role in dormancy onset of litchi terminal buds by regulating moisture levels.