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Secondary soil salinization causes plant stress, which can be relieved by different ratios of red to far-red light (R:FR). Our study aimed to elucidate the role of low R:FR ratios treatments on photosynthesis and growth of tomato seedlings in salinized soils. Tomato seedlings were treated under three R:FR ratios and calcium nitrate was applied simultaneously. The results showed that the treatments under low R:FR ratios stimulated growth parameters of tomato seedlings under calcium nitrate stress, the best impact being achieved at the R:FR ratio of 0.7 in this experiment. Low R:FR ratios treatments increased proline content as well as PSII maximum efficiency, actual electron transport operating efficiency, and photochemical quenching of tomato seedlings under calcium nitrate stress but decreased the value of nonphotochemical quenching. Moreover, low R:FR ratios treatments promoted net photosynthetic rate and increased the expression of a Rubisco gene. In conclusion, low R:FR ratios treatments could improve the salt resistance of greenhouse tomato plants.

Mimicking enzyme specificity via construction of on-demand geometric structures on nanozymes is of great interest in recent years. Although building substrate-specific polymers on nanozymes has achieved great success, polymer-blocked active sites would inevitably lead to decreased activity of nanozymes. Here, we have developed three photoactive metal-organic framework (MOF)-based nanozymes (called 2D-TCPP, 3D-TCPP, and AD-TCPP), which have different geometric structures as well as unshielded active sites. Together with their structural variations and excellent photoresponsive oxidase-like activities, these photoactive nanozymes exhibit structure-dependent specificity for three kinds of substrates (typical oxidase substrates, organic pollutants, and antioxidants). Moreover, AD-TCPP and 3D-TCPP show potential applications for environmental protection and bioanalysis, respectively. This work offers a promising approach to the development of nanozymes with enzyme-like specificity.

BackgroundEnsete glaucum (2n = 2x = 18) is a giant herbaceous monocotyledonous plant in the small Musaceae family along with banana (Musa). A high-quality reference genome sequence of E. glaucum offers a vital genomic resource for functional and evolutionary studies of Ensete, the Musaceae, and more widely in the Zingiberales.FindingsUsing a combination of Illumina and Oxford Nanopore Technologies (ONT) sequencing, genome-wide chromosome conformation capture (Hi-C), and RNA survey sequence, we report a high-quality assembly of the 481.5Mb genome with 9 pseudochromosomes and 36,836 genes (BUSCO 94.7%). A total of 55% of the genome is composed of repetitive sequences with LTR-retroelements (37%) and DNA transposons (7%) predominant. The 5S and 45S rDNA were each present at one locus, and the 5S rDNA had an exceptionally long monomer length of c.1,056 bp, contrasting with the c. 450 bp monomer at multiple loci in Musa. A tandemly repeated c. 134 bp satellite, 1.1% of the genome (with no similar sequence in Musa), was present around all nine centromeres, with a LINE retroelement also found at Musa centromeres. The assembly, including centromeric positions, enabled us to characterize in detail the chromosomal rearrangements occurring between the x = 9 species and x = 11 species of Musa. Only one chromosome has the same gene content as M. acuminata (ma). Three ma chromosomes represent part of only one E. glaucum (eg) chromosome, while the remaining seven ma chromosomes are fusions of parts of two, three, or four eg chromosomes, demonstrating complex and multiple evolutionary rearrangements in the change between x = 9 and x = 11.ConclusionsThe advance towards a Musaceae pangenome including E. glaucum, tolerant of extreme environments, makes a complete set of gene alleles available for crop breeding and understanding environmental responses. The chromosome-scale genome assembly show how chromosome number evolves, and features of the rapid evolution of repetitive sequences.