Birch (Betula platyphylla Suk.) contains triterpenoids with anti-HIV and anti-tumor pharmacological activities. However, the natural abundance of these triterpenoids is low, and their chemical synthesis is costly. Transcription factors have the ability to regulate the metabolite pathways of triterpenoids via multi-gene control, thereby improving metabolite yield. Thus, transcription factors have the potential to facilitate the production of birch triterpenoids. Plant bHLH (basic helix-loop-helix) transcription factors play important roles in stress response and secondary metabolism. In this study, we cloned two genes, BpMYC4 and BpbHLH9, that encode bHLH transcription factors in Betula platyphylla Suk. The open reading frame (ORF) of BpMYC4 was 1452 bp and encoded 483 amino acids, while the ORF of BpbHLH9 was 1140 bp and encoded 379 amino acids. The proteins of BpMYC4 and BpbHLH9 were localized in the cell membrane and nucleus. The tissue-specific expression patterns revealed that BpMYC4 expression in leaves was similar to that in the stem and higher than in the roots. The expression of BpbHLH9 was higher in the leaves than in the root and stem. The expressions of BpMYC4 and BpbHLH9 increased after treatment with abscisic acid, methyl jasmonate, and gibberellin and decreased after treatment with ethephon. The promoters of BpMYC4 and BpbHLH9 were isolated using a genome walking approach, and 900-bp and 1064-bp promoter sequences were obtained for BpMYC4 and BpbHLH9, respectively. The ORF of BpbHLH9 was ligated into yeast expression plasmid pYES3 and introduced into INVScl and INVScl1-pYES2-SS yeast strains. The squalene and total triterpenoid contents in the different INVScl1 transformants decreased in the following order INVScl1-pYES-SS-bHLH9 > INVScl1-pYES3-bHLH9 > INVScl1-pYES2- BpSS > INVScl-pYES2. In BpbHLH9 transgenic birch, the relative expression of the genes that encodes for enzymes critical for triterpenoid synthesis showed a different level of up-regulation compair with wild birch(control), and the contents of betulinic acid, oleanolic acid and betulin in bHLH9–8 transgenic birch were increased by 11.35%, 88.34% and 23.02% compared to in wild birch, respectively. Our results showed that the modulation of BpbHLH9 by different hormones affected triterpenoid synthesis and triterpenoid contents. This is the first report of the cloning of BpbHLH9, and the findings are important for understanding the regulatory role of BpbHLH9 in the synthesis of birch triterpenoids.

Maize leaf spot occurs worldwide and affects maize production. Maize can be infected by several pathogens causing leaf spot, such as Bipolaris zeicola, Bipolaris maydis, Curvularia species, Alternaria species, etc. In the current study, 30 Epicoccum isolates recovered from symptomatic maize leaves were identified based on morphological characteristics, pathogenicity, and multilocus sequence analyses of nuLSU, ITS, tub2, and rpb2. These maize isolates were grouped into five Epicoccum species, including E. nigrum, E. layuense, E. sorghinum, E. latusicollum, and E. pneumoniae. Pathogenicity tests showed that all five Epicoccum species could produce small ellipse- and spindle-shaped spots on maize leaves. The lesion center was grayish yellow to dark gray and surrounded by a chlorotic area. Furthermore, the Epicoccum isolates exhibited high pathogenicity to 20 main maize varieties of Heilongjiang Province but showed different sensitivities to the commonly used fungicides carbendazim and tebuconazole. In addition, these Epicoccum isolates showed different production capacity of pectinase, cellulase, protease, amylase, laccase, and gelatinase, but all showed high lipase activity. This is the first report globally of E. layuense, E. latusicollum, and E. pneumoniae as causal agents of maize leaf spot. E. pneumoniae was first reported as a plant pathogen.

Elucidating the mechanisms underlying the relationships between root growth and water use efficiency is important for achieving full yield potential. We conducted a field experiment with maize under high planting density (105,000 plants ha⁻¹) in 2013 and 2014. Four treatments were implemented: traditional cultivation, root optimization cultivation, canopy optimization cultivation, and shoot–root optimization cultivation. Compared to the treatments involving rotary tillage, subsoil tillage significantly improved the soil structure and promoted soil water storage. Moreover, the distribution of roots was significantly deeper under shoot–root optimization cultivation than traditional cultivation treatment. Shoot dry matter and leaf area were slightly higher under the plant growth-regulator treatments than that under the other treatments. Thus, relative to the shoot–root optimization cultivation treatment, the root optimization cultivation and canopy optimization cultivation treatments reduced the shoot–root area ratio by 8% and 4%, respectively, and these reductions were significantly lower than the reduction under the traditional cultivation treatment (16%). Rainfall storage can be enhanced by improving tillage practices, promoting root growth (particularly at depths >20 cm), promoting access to water, and regulating plant growth by the foliar spraying of ECK (ethylene-chlormequat-potassium). This approach has the potential to achieve highly efficient resource utilization without additional inputs, thereby increasing yield.

Long-chain acyl-CoA synthases (LACSs) are a key factor in the formation of acyl-CoA after fatty acid hydrolysis and play an important role in plant stress resistance. This gene family has not been research in soybeans. In this study, the soybean (Glycine max (L.) Merr.) whole genome was identified, the LACS family genes of soybean were screened, and the bioinformatics, tissue expression, abiotic stress, drought stress and co-expression of transcription factors of the gene family were analyzed to preliminarily clarify the function of the LACS family of soybean. A total of 17 LACS genes were screened from soybean genome sequencing data. A bioinformatics analysis of the GmLACS gene was carried out from the aspects of phylogeny, gene structure, conserved sequence and promoter homeopathic element. The transcription spectra of GmLACSs in different organs and abiotic stresses were used by qRT-PCR. The GmLACS genes, which co-expresses the significant response of the analysis of drought stress and transcription factors. The results showed that all soybean LACS have highly conserved AMP-binding domains, and all soybean LACS genes were divided into 6 subfamilies. Transcriptome analysis indicated that the gene-encoding expression profiles under alkali, low temperature, and drought stress. The expression of GmLACS9/15/17 were significantly upregulated under alkali, low temperature and drought stress. Co-expression analysis showed that there was a close correlation between transcription factors and genes that significantly responded to LACS under drought stress. These results provide a theoretical and empirical basis for clarifying the function of LACS family genes and abiotic stress response mechanism of soybean.

Soybean (Glycine max L.) holds significant global importance and is extensively cultivated in Heilongjiang Province, China. Soybean can be infected by Fusarium species, causing root rot, seed decay, stem rot, and leaf blight. In 2021 to 2022, a field survey of soybean diseases was carried out in 11 regions of Heilongjiang Province, and 186 soybean leaves with leaf blight symptoms and 123 soybean roots with root rot symptoms were collected. Unexpectedly, a considerable number of Fusarium isolates were obtained not only from root samples but also from leaf samples. A total of 584 Fusarium isolates (416 from leaves and 168 from roots) were obtained and identified as 18 Fusarium species based on morphological features and multilocus phylogenetic analyses with tef1 and rpb2 sequences. Fusarium graminearum and Fusarium sp. 1 in FOSC were the dominant species within soybean leaf and root samples, respectively. Pathogenicity tests were conducted for all Fusarium isolates on both soybean leaves and roots. Results showed that F. graminearum, F. ipomoeae, F. citri, F. compactum, F. flagelliforme, F. acuminatum, and F. sporotrichioides were pathogenic to both soybean leaves and roots. F. solani, F. avenaceum, F. pentaseptatum, F. serpentinum, F. annulatum, and Fusarium sp. 1 in FOSC were pathogenic to soybean roots, not to leaves. To our knowledge, this is the first study to thoroughly investigate soybean-associated Fusarium populations in leaves and roots in Heilongjiang Province.