The basic helix-loop-helix (bHLH) families that act as transcription factors play a central role in regulating a wide range of physiological, metabolic, and developmental processes in higher organisms. Systematic identification and characterization of bHLH gene families has not yet been performed in sugarcane. In the present study, 37 SsbHLH genes (101 total alleles) were identified in Saccharum spontaneum (Ss), with 1–4 alleles each. Phylogenetic analysis indicated that these SsbHLH could be classified into 17 subfamilies according to bHLH domains. All of the SsbHLHs were localized on 20 chromosomes, and the SsbHLH member’s likely arose through gene duplication. Based on a sugarcane transcriptome dataset trigged by Acidovorax avenae subsp. avenae (Aaa) causing red stripe, SsbHLH27 and SsbHLH36 were significantly upregulated by 1.12- to 5.96-fold [log₂(Fold Change)] in cultivar ROC22 (red stripe resistant), while both genes were significantly depressed in cultivar MT11-610 (red stripe susceptible) under Aaa infection. Based on another sugarcane transcriptome dataset trigged by Xanthomonas albilineans (Xa) causing leaf scald, four genes (SsbHLH03/04/36/37) were highly upregulated by 1.23- to 5.11-fold [log₂(Fold Change)] in LCP85-384 (leaf scald-resistant), but downregulated or non-significantly changed in cultivar ROC20 (leaf scald-susceptible) under Xa infection. SsbHLH15/17 were positively induced by both Aaa and Xa stimuli, whereas SsbHLH30/33 were negatively regulated by both pathogens. Some genes, such as SsbHLH06/11, had different expression profiles under the two pathogens infections, showing increased expression after Aaa infection but reduced expression with Xa. These findings provide important candidate genes for further functional analyses in sugarcane in response to bacterial stress.

用作转录因子的基本螺旋-环-螺旋（bHLH）家族在调节高等生物的各种生理，代谢和发育过程中起着核心作用。bHLH基因家族的系统鉴定和表征尚未在甘蔗中进行。在本研究中，37个SsbHLH基因（101个总等位基因）中被鉴定甜根子（SS），其中每个1-4等位基因。系统发育分析表明，根据bHLH结构域，这些SsbHLH可分为17个亚家族。所有的SsbHLH都位于20条染色体上，而SsbHLH成员可能是通过基因复制产生的。基于一个甘蔗转录组数据集触发的Acidovorax avenae  subsp 。引起红色条纹的avenae  （Aaa）在ROC22品种中对SsbHLH27和SsbHLH36的表达显着上调了1.12倍至5.96倍（对数₂（倍数变化））（对红色条纹的抵抗力），而在MT11-610品种中两个基因均显着下调（红色条纹易感）受到Aaa感染。基于另一种由甘蔗黄单胞菌（Xa）触发导致叶片烫伤的甘蔗转录组数据集，四个基因（SsbHLH03 / 04/36/37）在LCP85-384（耐叶鳞病）中被高度上调1.23至5.11倍（log ₂（倍数变化）），但在Xa感染下，ROC20品种（对叶鳞病敏感）被下调或无显着变化。SsbHLH15 / 17被Aaa和Xa刺激均阳性诱导，而SsbHLH30 / 33被这两种病原体均负调控。某些基因，例如SsbHLH06 / 11在两种病原体感染下具有不同的表达谱，显示在Aaa感染后表达增加，但用Xa减少表达。这些发现为重要的候选基因提供了重要的候选基因，用于甘蔗响应细菌胁迫的进一步功能分析。