The mitogen-activated protein kinase (MAPK) pathway is a widely distributed signaling cascade in eukaryotes and is involved in regulating plant growth, development, and stress responses. High temperature, a frequently occurring environmental stressor, causes premature bolting in lettuce with quality decline and yield loss. However, whether MAPKs play roles in thermally induced bolting remains poorly understood. In this study, 17 LsMAPK family members were identified from the lettuce genome. The physical and chemical properties, subcellular localization, chromosome localization, phylogeny, gene structure, family evolution, cis-acting elements, and phosphorylation sites of the LsMAPK gene family were evaluated via in silico analysis. According to phylogenetic relationships, LsMAPKs can be divided into four groups, A, B, C, and D, which is supported by analyses of gene structure and conserved domains. The collinearity analysis showed that there were 5 collinearity pairs among LsMAPKs, 8 with AtMAPKs, and 13 with SlMAPKs. The predicted cis-acting elements and potential phosphorylation sites were closely associated with hormones, stress resistance, growth, and development. Expression analysis showed that most LsMAPKs respond to high temperatures, among which LsMAPK4 is significantly and continuously upregulated upon heat treatments. Under heat stress, the stem length of the LsMAPK4-knockdown lines was significantly shorter than that of the control plants, and the microscope observations demonstrated that the differentiation time of flower buds at the stem apex was delayed accordingly. Therefore, silencing of LsMAPK4 significantly inhibited the high- temperature-accelerated bolting in lettuce, indicating that LsMPAK4 might be a potential regulator of lettuce bolting. This study provides a theoretical basis for a better understanding of the molecular mechanisms underlying the MAPK genes in high-temperature-induced bolting.

The U-box E3 (PUB) family genes encode the E3 ubiquitin ligase enzyme, which determines substrate specific recognition during protein ubiquitination. They are widespread in plants and are critical for plant growth, development, and response to external stresses. However, there are few studies on the functional characteristic of PUB gene family in the important staple crop, maize (Zea mays L.). In this study, the PUB gene in maize was aimed to identify and classify through whole-genome screening. Phylogenetic tree, gene structure, conserved motif, chromosome location, gene duplication (GD), synteny, and cis-acting regulatory element of PUB member were analyzed. The expression profiles of ZmPUB gene family in maize during development and under abiotic stress and hormones treatment were analyzed by the RNA-seq data. A total of 79 PUB genes were identified in maize genome, and they were stratified into seven categories. There were 25 pairs of segmental duplications (SD) and 1 pair of tandem duplication (TD) identified in the maize PUB gene family. A close relationship was observed between the monocot plant maize and rice in PUB gene family. There were 94 kinds of cis-acting elements identified in the maize PUB gene family, which included 46 biotic- and abiotic-responsive elements, 19 hormone-responsive elements, 13 metabolic and growth-related elements. The expression profiles of maize PUB gene family showed characteristics of tissue specificity and response to abiotic stress and hormones treatment. These results provided an extensive overview of the maize PUB gene family.

Lettuce (Lactuca sativa L.) being a cool‐season crop can bolt if the temperatures increase above 20 °C. When lettuce bolts, the plants start the reproductive growth cycle. The improvement in resistance to high temperature bolting has been an important goal of lettuce breeding. This paper verified that Lactuca sativa mitogen‐activated protein kinases 6 (LsMAPK6) played an important role in high temperature bolting. The full‐length CDS of LsMAPK6 gene was amplified by real‐time polymerase chain reaction (RT‐PCR) and analyzed by bioinformatics software. The expression of LsMAPK6 was determined by quantitative real‐time polymerase chain reaction (qRT‐PCR). The results showed that the length of LsMAPK6 was 1,182 bp, encoding 393 amino acids. The protein domain was STKc_TEY_MAPK and closely relevant to sunflower (Helianthus annuus L.), mouse‐ear cress [Arabidopsis thaliana (L.) Heynh.], and chrysanthemum (Chrysanthemum morifolium Ramat.). The qRT‐PCR showed that Lsmapk6 was mainly expressed in stem, stem apex, and taproot, and high temperature significantly promoted its expression. Virus‐induced gene silencing (VIGS) technology successfully silenced LsMAPK6 in lettuce, and the bolting of silenced lines was delayed under the action of high temperature and exogenous gibberellin. These suggest that LsMAPK6 plays an important role in promoting bolting. This study laid a foundation for further study on the function and regulation mechanism of MAPK6.

The primary parts of corn stalks are the leaves and the stems, which comprise the cortex and the pith. Corn has long been cultivated as an grain crops, and now it is a primary global source of sugar, ethanol, and biomass-generated energy. Even though increasing the sugar content in the stalk is an important breeding goal, progress has been modest in many breeding researchers. Accumulation is the gradual rise in quantity when new additions are made. The challenging characteristics of such sugar content in corn stalks are below the protein, bio-economy, and mechanical injury. Hence, in this research, plant water-content-enabled micro-Ribonucleic acids (PWC-miRNAs) were designed to increase the sugar content in corn stalks following an accumulation rule. High-throughput sequencing of the transcriptome, short RNAs, and coding RNAs was performed here; leaf and stem degradation from two early-maturing Corn genotypes revealed new information on miRNA-associated gene regulation in corn during the sucrose accumulation process. For sugar content in corn stalk, PWC-miRNAs were used to establish the application of the accumulation rule for data-processing monitoring throughout. Through simulation, management, and monitoring, the condition is accurately predicted, providing a new scientific and technological means to improve the efficiency of the construction of sugar content in corn stalks. The experimental analysis of PWC-miRNAs outperforms sugar content in terms of performance, accuracy, prediction ratio, and evaluation. This study aims to provide a framework for increasing the sugar content of corn stalk.

In order to reduce the harmful effects of nisulfuron on sweet corn, the physiological regulation mechanism of sweet corn detoxification was studied. In this study, a pair of sister lines of sweet corn(nicosulfuron-tolerant“HK310” and nicosulfuron-sensitive “HK320”)were used to analyze the effects of nicosulfuron stress on glyoxalase system, hormone content and key gene expression on sweet corn seedlings. The results showed that after spraying nicosulfuron, methyl glyoxal (MG) content in HK301 increased first and then decreased. As well as, the activities of glyoxalaseI (GlyI) and glyoxalaseII (GlyII), the content of non-enzymatic glutathione (GSH) and the glutathione redox state glutathione/ (glutathione + glutathione disulfide) (GSH/ (GSH + GSSG)) showed the same trend as the MG content. Besides, the contents of ababic acid (ABA), gibberelin (GA) and zeatin nucleoside (ZR) also increased first and then decreased, and auxin (IAA) content increased continuously. In HK301, all indexes after spraying nicosulfuron were significantly greater than those of control. In HK320, MG accumulation continued to increase after nicosulfuron spraying, and the activities of GlyI and GlyII and GSH content first increased and then decreased after 1d stress. The indicators above are significantly greater than the control. While the ratio of GSH/ (GSH + GSSG) showed a decreasing trend and significantly smaller than the control. Furthermore, the contents of ABA and IAA continued to increase, and the contents of GA and ZR first increased and then decreased. Compared with HK320, HK301 significantly upregulated the transcription levels of GlyI and GlyII genes in roots, stems and leaves. Comprehensive analysis showed that sweet maize seedlings with different drug resistance improved their herbicide resistance by changing glyoxalase system and regulating endogenous hormones. The results provided a theoretical basis for further understanding the response mechanism of glyoxalase system and the regulation characteristics of endogenous hormones in maize under the stress of nianysulfuron.