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Here, we present the draft genome (377.3 Mbp) of Corchorus olitorious cv. JRO-524 (Navin), which is a leading dark jute variety developed from a cross between African (cv. Sudan Green) and indigenous (cv. JRO-632) types. We predicted from the draft genome a total of 57,087 protein-coding genes with annotated functions. We identified a large number of 1765 disease resistance-like and defense response genes in the jute genome. The annotated genes showed the highest sequence similarities with that of Theobroma cacao followed by Gossypium raimondii. Seven chromosome-scale genetically anchored pseudomolecules were constructed with a total size of 8.53 Mbp and used for synteny analyses with the cocoa and cotton genomes. Like other plant species, gypsy and copia retrotransposons were the most abundant classes of repeat elements in jute. The raw data of our study are available in SRA database of NCBI with accession number SRX1506532. The genome sequence has been deposited at DDBJ/EMBL/GenBank under the accession LLWS00000000, and the version described in this paper will be the first version (LLWS01000000).

Bast fibre development in jute (Corchorus spp.) is a complex process that involves the differentiation of secondary phloic fibres (SPF) from the cambium followed by lignification of the fibre wall. We have identified a unique radiation-induced bast fibre-shy mutant of dark jute (C. olitorius L.), which is concurrently defective in the differentiation of SPF and secondary xylem (wood) but develops lignified fibre cells. It displays the most unusual phenotype with stunted growth and abnormal leaf shape, matures earlier, yields significantly less bast fibres and wood, and produces poorer quality fibres than its parental wild-type. Cambial activities in the mutant and the normal type were monitored by estimating the fibre content that entails the total number of fibre cell bundles (FCBs) in an entire transversal section. The results show that a multifold reduction of bast fibre yield in the mutant is related to development-specific loss of cambium function along the length of the stem from to top to bottom. Since lignification of the fibre wall in the mutant is not only normal but also developmentally uniform, cambium function may be unrelated to the lignification process during bast fibre development. Lignin does not influence bast fibre strength and fineness. The architecture of the mostly triangular FCB wedges, which is governed by a balanced growth between radially elongating FCBs and tangentially expanding ray cells due to development-specific activation of the fusiform and ray initials of the cambium, conditions fibre fineness. Our study shows that mutation could specifically impair the cambial activity by rendering those initials that differentiate the SPF and secondary xylem nonfunctional.

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