Biomass Accumulation and Cell Wall Structure of Rice Plants Overexpressing a Dirigent-Jacalin of Sugarcane (ShDJ) Under Varying Conditions of Water Availability

Abstract

A sugarcane gene encoding a dirigent-jacalin , ShDJ , was induced under drought stress. To elucidate its biological function, we integrated a ShDJ -overexpression construction into the rice Nipponbare genome via Agrobacterium -mediated transformation. Two transgenic lines with a single copy gene in T 0 were selected and evaluated in both the T 1 and T 4 generations. Transgenic lines had drastically improved survival rate under water deficit conditions, at rates close to 100%, while WT did not survive. Besides, transgenic lines had improved biomass production and higher tillering under water deficit conditions compared with WT plants. Reduced pectin and hemicellulose contents were observed in transgenic lines compared with wild-type plants under both well-watered and water deficit conditions, whereas cellulose content was unchanged in line #17 and reduced in line #29 under conditions of low water availability. Changes in lignin content under water deficit were only observed in line #17. However, improvements in saccharification were found in both transgenic lines along with changes in the expression of OsNTS1/2 and OsMYB58/63 secondary cell wall biosynthesis genes. ShDJ -overexpression up-regulated the expression of the OsbZIP23 , OsGRAS23 , OsP5CS , and OsLea3 genes in rice stems under well-watered conditions. Taken together, our data suggest that ShDJ has the potential for improving drought tolerance, plant biomass accumulation, and saccharification efficiency.

Differential Response of Two Tomato Genotypes, Wild Type cv. Ailsa Craig and Its ABA-Deficient Mutant flacca to Short-Termed Drought Cycles

“…Increased lignin deposition and up-regulation of enzymes related to its biosynthesis and accumulation under drought conditions were also reported in numerous articles [113][114][115][116]. In this way, lignin prevents water loss from the leaf, thus contributing to drought tolerance [116].…”

Genome-wide identification and expression analysis of dirigent-jacalin genes from plant chimeric lectins in Moso bamboo (Phyllostachys edulis)

“…JRL fusions to other proteins may have been required for the development of new functions and previous research has found D-J genes which appear to be involved in responses to specific biotic or abiotic stimuli [25,53,76,86]. These genes may therefore have evolved via extension of the jacalin domain in JRLs and the fusion of other functional domains that helped plants adapt to various environmental challenges [85].…”

“…Studies have shown that DIR genes are involved in disease resistance responses and may affect the sugar-binding specificity of the entire lectin protein [41,51]. In sugarcane (Saccharum officinarum), JRL domains affiliated with a dirigent domain (Dirigent-Jacalin or D-J) have been shown to play a part in drought tolerance [53].…”

“…Andrade et al [53] described the role that the JRL domain plays in conjunction with the dirigent domain (dirigent-jacalin, or DJ) in drought tolerance, thus demonstrating the role of chimeric lectin in abiotic stress. Thus far, genome-wide analysis of SBP-like [53], ARF [54], MADS-box [55], UBP [56], MYB [57] and other gene families has been performed in Moso bamboo, but there is little known about the occurrence of different D-J lectins within bamboo species, despite the sequencing of its genome several years ago [58]. The new assembly of the Moso bamboo genome offers an opportunity to improve our understanding of the abundance, distribution and expansion of bamboo lectins [59].…”

Genome-Wide Characterization of Dirigent Proteins in Populus: Gene Expression Variation and Expression Pattern in Response to Marssonina brunnea and Phytohormones

“…DIR genes can respond to many types of biotic and abiotic stresses. In terms of responding to abiotic stresses (salt, drought, high/low temperature, pesticide residue, waterlogging, and H 2 O 2 ), there is evidence of ScDIR in sugarcane [25], OsDIRs and ShDJ in rice [26,27], BrDIRs in Brassica [28], BhDIR1 in Boea hygrometrica [29], and CsDIR16 in cucumber [30] responding to them. In terms of resistance to insect and pathogen stresses induced by weevils or mechanical damage, six DIR genes from Sitka spruce (Picea sitchensis) bark can be expressed rapidly and strongly (up to 500-fold) [22].…”