SummaryZinc (Zn) is an essential micronutrient in plants. The activity of copper/zinc superoxide dismutase (CSD) and carbonic anhydrase (CA) correlate with differences in Zn efficiency in plants; therefore, it is reasonable to hypothesize the existence of a Zn economy model that saves Zn for these essential Zn proteins during Zn deficiency. However, up to this point, direct evidence for the idea that CSD and/or CA might be priorities for Zn delivery has been lacking.Here, we investigated the spatial-temporal effects of acute Zn depletion and resupply by integrating physiological studies and molecular analyses using hydroponically grown Sorghum.The elevated expression of miR398 repressed CSD expression in roots, whereas the reduced expression of miR528 resulted in a relatively stable level of CSD expression in Sorghum leaves under Zn depletion.Spatial-temporal analysis after Zn resupply to previously depleted plants revealed that the expression and activity of CA were the first to recover after Zn addition, whereas the recovery of the activities of CSD and alcohol dehydrogenase (ADH) was delayed, suggesting that CA receives priority in Zn delivery over CSD and ADH. Our results also indicate that microRNAs (miRNAs) are important regulators of the response of Zn deficiency in plants.

MADS-box transcription factors play significant roles in plant developmental processes such as floral organ conformation, flowering time, and fruit development. Pear (Pyrus), as the third-most crucial temperate fruit crop, has been fully sequenced. However, there is limited information about the MADS family and its functional divergence in pear. In this study, a total of 95 MADS-box genes were identified in the pear genome, and classified into two types by phylogenetic analysis. Type I MADS-box genes were divided into three subfamilies and type II genes into 14 subfamilies. Synteny analysis suggested that whole-genome duplications have played key roles in the expansion of the MADS family, followed by rearrangement events. Purifying selection was the primary force driving MADS-box gene evolution in pear, and one gene pairs presented three codon sites under positive selection. Full-scale expression information for PbrMADS genes in vegetative and reproductive organs was provided and proved by transcriptional and reverse transcription PCR analysis. Furthermore, the PbrMADS11(12) gene, together with partners PbMYB10 and PbbHLH3 was confirmed to activate the promoters of the structural genes in anthocyanin pathway of red pear through dual luciferase assay. In addition, the PbrMADS11 and PbrMADS12 were deduced involving in the regulation of anthocyanin synthesis response to light and temperature changes. These results provide a solid foundation for future functional analysis of PbrMADS genes in different biological processes, especially of pigmentation in pear.

Key message Candidate genes were identified and the role of phytohormones such as JA-Me and ABA in the synthesis of S-RNase was emphasized in pear selfincompatibility. Abstract Self-incompatibility (SI) occurs widely in flowering plants as an intraspecific reproductive barrier. This phenomenon promotes variation within species, but for some species such as Pyrus, SI is a nuisance rather than a benefit in agricultural production. Although many studies have been conducted on SI in pears, its mechanism remains unclear. In this study, high-throughput Illumina RNA sequencing (RNA-seq) was used to identify SI-related genes in pear styles. Using transcriptome comparisons, differentially expressed genes of unpollinated (UP), crosspollinated (CP), and self-pollinated (SP) styles were identified after 48 h. A total of 1796 and 1890 genes were identified in DSC (UP vs. CP) and DSI (UP vs. SP), respectively. KEGG analysis revealed that genes involved in the ''plant hormone signal transduction pathway'' and ''plant-pathogen interaction pathway'' were significantly enriched in DSI (UP vs. SP) compared to those in DSC (UP vs. CP). The expression level of S-glycoprotein ribonuclease (S-RNase) was dramatically reduced in cross-pollinated (CP) styles. To better understand the relationship between the expression patterns of S-RNase and two major KEGG pathways, the concentrations of phytohormones were measured, and the expression pattern of S-RNase was analysed using qRT-PCR. Our results demonstrate that methyl jasmonate and abscisic acid may enhance the expression level of S-RNase, and pollination can affect the synthesis of methyl jasmonate and abscisic acid in pear styles. Overall, this study is a global transcriptome analysis of SI in pear. A relationship between self-rejection, plant hormones, and pathogen defence was shown in pear.Keywords Pear (Pyrus bretschneideri Rehd.) Á Selfincompatibility Á Transcriptome Á S-RNase Á Methyl jasmonate

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Salt decreases the uptake of Zn and other minerals and causes nutritional disorders in plants. Zn is an essential micronutrient for all organisms and it is reasonable to hypothesize that Zn status is essential for maintaining salt tolerance in plants. In this study, the physiological and molecular mechanisms of Zn-based alleviation of salt stress in wheat seedlings were investigated. Our results indicate that sufficient Zn nutrition maintained antioxidative enzyme activities and decreased a reactive oxygen species over-accumulation in wheat seedlings. Our data also reveal that sufficient Zn nutrition improved the expression of Na + /H + antiporter genes, TaSOS1 and TaNHX1, thereby decreasing the Na + accumulation and subsequently improving salt tolerance in wheat seedlings.Additional key words: antioxidative enzyme, ascorbate peroxidase, Na + /H + antiporter, peroxidase, superoxide dismutase, Triticum aestivum.