Search

Background and aims: Soil acidification impedes crop growth. Seed pelletization was used to improve crop resistance to various stress environments but not acidic soil. This study aimed to develop rapeseed seed pelletization and to assess the promotional effects of pelletization on rapeseed growth under acidic conditions. Methods: Two main acid-resistant functional agents (Ca(OH)2, and biochar) and a basic formula including sodium carboxymethyl cellulose, H3BO3, nano-silica, brassinolide, sodium naphthalene acetate, indoleacetic acid, and yeast metabolite were used to evaluate the effects on rapeseed growth by seed pelletization. Then, the mechanism of alleviating acidic stress by seed pelletization was investigated. Results: A basic formula were developed by soil test. Three acid-resistant seed pelletization cases (① 0.5% Ca(OH)2 + a basic formula; ② 10% biochar + a basic formula; ③ 0.25% Ca(OH)2 + 5% biochar + a basic formula) were confirmed to have significant plant growth promotion. Compared to the unpelletized treatment, seed pelletization significantly increased root length and dry weight of rapeseed seedling by 67.32%-78.34% and 46.47%-74.12%, respectively. It also increased nutrient uptake and reduced the accumulation of toxic Al by 11.72%-16.23% in rapeseed roots. Moreover, seed pelletization modulated the local soil environment at the sowing site, increased soil pH by 0.88–1.11 in the microzone, thereby reducing the adverse effects of acidic stress. Conclusion: Seed pelletization in rapeseed can enhance its tolerance to acidic stress and promote plant growth. Additionally, our results provide new insights into the strategies to alleviate the inhibitory effects of acidic soil. [ABSTRACT FROM AUTHOR]

Summary: CRISPR/Cas‐base editing is an emerging technology that could convert a nucleotide to another type at the target site. In this study, A3A‐PBE system consisting of human A3A cytidine deaminase fused with a Cas9 nickase and uracil glycosylase inhibitor was established and developed in allotetraploid Brassica napus. We designed three sgRNAs to target ALS, RGA and IAA7 genes, respectively. Base‐editing efficiency was demonstrated to be more than 20% for all the three target genes. Target sequencing results revealed that the editing window ranged from C1 to C10 of the PAM sequence. Base‐edited plants of ALS conferred high herbicide resistance, while base‐edited plants of RGA or IAA7 exhibited decreased plant height. All the base editing could be genetically inherited from T0 to T1 generation. Several Indel mutations were confirmed at the target sites for all the three sgRNAs. Furthermore, though no C to T substitution was detected at the most potential off‐target sites, large‐scale SNP variations were determined through whole‐genome sequencing between some base‐edited and wild‐type plants. These results revealed that A3A‐PBE base‐editing system could effectively convert C to T substitution with high‐editing efficiency and broadened editing window in oilseed rape. Mutants for ALS, IAA7 and RGA genes could be potentially applied to confer herbicide resistance for weed control or with better plant architecture suitable for mechanic harvesting. [ABSTRACT FROM AUTHOR]

Long-chain acyl-Coenzyme A (CoA) synthetases (LACSs) catalyze the formation of long-chain acyl-CoA, and play important roles in fatty acid metabolism including phospholipids, triacylglycerol (TAG) biosynthesis and fatty acid β-oxidation. Here, we report the characterization of a LACS gene from Brassica napus. It is highly homologous to Arabidopsis LACS4 and thus designated as BnLACS4. The cloned gene BnLACS4 could complement a LACS-deficient yeast strain YB525. It is mainly expressed in flowers and developing seeds where lipid biosynthesis is at high rate in Brassica napus. When transiently expressed in tobacco leaves, BnLACS4 is localized in endoplasmic reticulum (ER), the common site for eukaryotic pathway of lipid biosynthesis. Expression of BnLACS4 in the yeast strain pep4 increased its lipid content. Taken together, our results suggest that BnLACS4 may be involved in lipid biosynthesis in B. napus.

Salinity is one of the major constraints in oilseed rape ( Brassica napus L.) production. One of the means to overcome this constraint is the use of plant growth regulators to induce plant tolerance. To study the plant response to salinity in combination with a growth regulator, 5-aminolevulinic acid (ALA), oilseed rape plants were grown hydroponically in greenhouse conditions under three levels of salinity (0, 100, and 200 mM NaCl) and foliar application of ALA (30 mg/l). Salinity depressed the growth of shoots and roots, and decreased leaf water potential and chlorophyll concentration. Addition of ALA partially improved the growth of shoots and roots, and increased the leaf chlorophyll concentrations of stressed plants. Foliar application of ALA also maintained leaf water potential of plants growing in 100 mM salinity at the same level as that of the control plants, and there was also an improvement in the water relations of ALA-treated plants growing in 200 mM. Net photosynthetic rate and gas exchange parameters were also reduced significantly with increasing salinity; these effects were partially reversed upon foliar application with ALA. Sodium accumulation increased with increasing NaCl concentration which induced a complex response in the macro-and micronutrients uptake and accumulation in both roots and leaves. Generally, analyses of macro- (N, P, K, S, Ca, and Mg) and micronutrients (Mn, Zn, Fe, and Cu) showed no increased accumulation of these ions in the leaves and roots (on dry weight basis) under increasing salinity except for zinc (Zn). Foliar application of ALA enhanced the concentrations of all nutrients other than Mn and Cu. These results suggest that under short-term salinity-induced stress (10 days), exogenous application of ALA helped the plants improve growth, photosynthetic gas exchange capacity, water potential, chlorophyll content, and mineral nutrition by manipulating the uptake of Na+. [ABSTRACT FROM AUTHOR]