Lichens have been widely studied for their symbiotic properties and for the secondary metabolites production by its fungal symbiont. Recent molecular studies have confirmed coexistence of bacteria along with the fungal and algal symbionts. Direct nucleic acid study by -omics approaches is providing better insights into their structural and functional dynamics. However, genomic analysis of individual members of lichen is difficult by the conventional approach. Hence, genome assembly from metagenome data needs standardization in the eukaryotic system like lichens. The present study aimed at metagenomic characterization of rock associated lichen Dirinaria collected from Kutch and Dang regions of Gujarat, followed by genome reconstruction and annotation of the mycobiont Dirinaria. The regions considered in the study are eco-geographically highly variant. The results revealed higher alpha diversity in the dry region Kutch as compared to the tropical forest associated lichen from Dang. Ascomycota was the most abundant eukaryote while Proteobacteria dominated the bacterial population. There were 23 genera observed only in the Kutch lichen (KL) and one genus viz., Candidatus Vecturithrix unique to the Dang lichen (DL). The exclusive bacterial genera in the Kutch mostly belonged to groups reported for stress tolerance and earlier isolated from lithobionts of extreme niches. The assembled data of KL & DL were further used for genome reconstruction of Dirinaria sp. using GC and tetra-pentamer parameters and reassembly that resulted into a final draft genome of 31.7 Mb and 9556 predicted genes. Twenty-eight biosynthesis gene clusters were predicted that included genes for polyketide, indole and terpene synthesis. Association analysis of bacteria and mycobiont revealed 8 pathways specific to bacteria with implications in lichen symbiosis and environment interaction. The study provides the first draft genome of the entire fungal Dirinaria genus and provides insights into the Dirinaria lichen metagenome from Gujarat region.

地衣的共生特性及其真菌共生体产生的次生代谢产物已被广泛研究。最近的分子研究证实细菌与真菌和藻类共生体共存。通过组学方法进行的直接核酸研究为他们的结构和功能动力学提供了更好的见识。然而，通过常规方法难以对地衣的单个成员进行基因组分析。因此，从元基因组数据中提取基因组需要在地衣等真核系统中进行标准化。本研究旨在从古吉拉特邦库奇和当地区采集的与岩石相关的地衣狄氏菌的宏基因组学表征，然后进行基因组重建和分生菌素狄氏菌的注释。该研究中考虑的区域在生态地理上存在很大差异。结果表明，与Dang的热带森林相关地衣相比，干燥地区Kutch的α多样性更高。子囊菌是最丰富的真核生物，而变形杆菌则主导细菌种群。仅在Kutch地衣（KL）中观察到23个属，而Dang地衣（DL）中唯一的一个属Candidatus Vecturithrix被观察到。Kutch的独有细菌属大部分属于报道的耐胁迫性群体，并且较早地从极端生态位的石斑鱼中分离出来。KL和DL的组装数据进一步用于Dirinaria sp。的基因组重建。使用GC和四pentamer参数并进行重组，最终形成了31.7 Mb和9556个预测基因的最终基因组草图。预测有28个生物合成基因簇，其中包括聚酮化合物，吲哚和萜烯合成的基因。细菌与分枝杆菌的关联分析揭示了细菌特有的8条途径，这些途径与地衣共生和环境相互作用有关。该研究提供了整个真菌Dirinaria属的第一个基因组草图，并提供了对古吉拉特邦Dirinaria地衣基因组的见解。