Agaves, which have been grown commercially for fiber or alcoholic beverages, are emerging as a candidate crop for biochemicals and biofuels production in semiarid regions because of their high productivity in low rainfall areas, drought tolerance, and low lignin content. In this work, we present the transcriptomic atlas of Agave sisalana, Agave fourcroydes, and agave hybrid 11648 (A. amaniensis x A. angustifolia) under prolonged drought in field conditions. Leaf, stem, and root tissues were sequenced, and gene expression profiles were correlated with biomass composition, enzymatic hydrolysis of cell wall carbohydrates, histochemical analysis, and non-structural carbohydrates content. Differences in biomass accessibility were attributed to either lignin content or lignin composition, possibly through modification of s/g ratio promoted by changes in Caffeic Acid 3-O-Methyltransferase (COMT) transcript abundance. Unlike most plants, the most highly expressed transcripts do not encode photosynthetic proteins, but rather involved in stress response. Although the three cultivars presented quantitative differences in global gene expression, they activated a highly overlapping set of genes. The main molecular strategies employed by agave to cope with high-temperature and drought seem to consist in overexpressing HSP and LEA, as well as promoting raffinose accumulation as an osmolyte. In conclusion, our data provide vital new genetic information for the study of Agave species and provide new insights into cell wall architecture, recalcitrance, and resistance to abiotic stresses for these species.

中文翻译：

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半干旱地区三种适合生化试剂和生物燃料生产的龙舌兰纤维生产品种的转录组分析

商业生产用于纤维或酒精饮料的龙舌兰正成为半干旱地区生物化学和生物燃料生产的候选作物，因为它们在低雨量地区具有较高的生产力，耐旱性和木质素含量低。在这项工作中，我们提出了在田间条件下长时间干旱下龙舌兰，龙舌兰和龙舌兰杂种11648（A. amaniensis x A. angustifolia）的转录组图谱。对叶，茎和根组织进行测序，并将基因表达谱与生物量组成，细胞壁碳水化合物的酶促水解，组织化学分析和非结构性碳水化合物含量相关。生物量可及性的差异归因于木质素含量或木质素组成，可能是由于咖啡酸3-O-甲基转移酶（COMT）转录本丰度的变化促进了s / g比例的改变。与大多数植物不同，表达最高的转录本不编码光合蛋白，而是参与胁迫反应。尽管这三个品种在总体基因表达上存在数量差异，但它们激活了一组高度重叠的基因。龙舌兰用于应对高温和干旱的主要分子策略似乎在于过表达HSP和LEA，以及促进作为渗透压的棉子糖积累。总之，我们的数据为龙舌兰物种的研究提供了至关重要的新遗传信息，并为这些物种的细胞壁结构，顽固性以及对非生物胁迫的抗性提供了新见解。