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Northeast India is known for its diverse nature of soil, climate, and topography that supports rich banana diversity. Banana (Musa sp.) is the second most important fruit crop in India due to its availability throughout the year, taste along with the nutritive and medicinal value. Thus, the genetic diversity of banana resources is essential for present and future food. This study aimed to determine the comparative genetic variation among 14 non-commercial edible banana cultivars of Assam, India, by using 50 different morphological characters with ISSR markers. Morphological data were analyzed hierarchical clusters and principal coordinates which showed to cluster all the accessions into two distinct groups and subsequently into four subgroups. Furthermore, ISSR markers revealed the average percentage of polymorphism. A total of 62 bands were detected of which 56 bands showed polymorphism using seven primers. The highest number of the band was detected with the primer UBC-843 and the lowest number of the band was observed with UBC-848. The genetic similarity index was prepared using Jaccard's similarity coefficient and the range of genetic similarity was from 0.28 to 0.77 with 0.51 of average. Dendrogram produced from the cluster analysis showed the clear division of the genotypes into two distinct clusters. Seven accessions of viz. Bharatmoni, Assamiya-malbhog, Gobin tulashi, Bokmoni, Bangali-malbhog, Katiya-jahaji, and Abormalbhog were clustered in the first group. The second group included the accessions viz. Jatikol, Adeel, Guwahatia-kol, Fessamonohar, Athiya kol, Ximalu-monohar, and Bogi-monohar. The Mantel test analysis also showed positive relationships between morphological traits and ISSR markers.

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Lowland acidic soils with water-logged regions are often affected by ferrous iron (Fe2+) toxicity, a major yield-limiting factor of rice production. Under severe Fe2+ toxicity, reactive oxygen species (ROS) are crucial, although molecular mechanisms and associated ROS homeostasis genes are still unknown. In this study, a comparative RNA-Seq based transcriptome analysis was conducted to understand the Fe2+ toxicity tolerance mechanism in aromatic Keteki Joha. About 69 Fe homeostasis related genes and their homologs were identified, where most of the genes were downregulated. Under severe Fe2+ toxicity, the biosynthesis of amino acids, RNA degradation, and glutathione metabolism were induced, whereas phenylpropanoid biosynthesis, photosynthesis, and fatty acid elongation were inhibited. The mitochondrial iron transporter (OsMIT), vacuolar iron transporter 2 (OsVIT2), ferritin (OsFER), vacuolar mugineic acid transporter (OsVMT), phenolic efflux zero1 (OsPEZ1), root meander curling (OsRMC), and nicotianamine synthase (OsNAS3) were upregulated in different tissues, suggesting the importance of Fe retention and sequestration for detoxification. However, several antioxidants, ROS scavenging genes and abiotic stress-responsive transcription factors indicate ROS homeostasis as one of the most important defense mechanisms under severe Fe2+ toxicity. Catalase (CAT), glutathione (GSH), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) were upregulated. Moreover, abiotic stress-responsive transcription factors, no apical meristem (NAC), myeloblastosis (MYB), auxin response factor (ARF), basic helix-loop-helix (bZIP), WRKY, and C2H2-zinc finger protein (C2H2-ZFP) were also upregulated. Accordingly, ROS homeostasis has been proposed as an essential defense mechanism under such conditions. Thus, the current study may enrich the understanding of Fe-homeostasis in rice.