Sucrose transporter (SUT) plays essential roles in plant growth and development, as well as responses to diverse abiotic stresses. However, limited information about the function of SUT was available in pineapple, an important tropical fruit crop with crassulacean acid metabolism. Here, four AcSUT genes were identified in pineapple genome, and divided into three clades according to the phylogenetic analysis. The expression profiles of AcSUTs were systemically examined, and they were all localized to plasma membrane. Transport activity assay by two-electrode voltage clamp of Xenopus oocytes showed that AcSUT1A and AcSUT1B were capable of transporting a range of glucosides, and they were exhibited high affinity for sucrose with Km value of 0.09 mM and 0.41 mM at pH 5.0, respectively. Overexpression of the cold-induced AcSUT1B conferred enhanced cold tolerance in transgenic Arabidopsis. DNA-protein interaction analysis further demonstrated that AcCBF1 directly binds the CRT/DRE element of the AcSUT1B promoter and activated its expression. Heterologous expression of AcCBF1 in Arabidopsis also increased cold tolerance. In this study, we investigated the transport activities of AcSUTs in pineapple and identified the AcCBF1-AcSUT1B module involved in cold stress, which provided new insights into the molecular mechanism of the cold response in pineapple.

Abstract Background: growth-regulating factors（GRFs）are plant-specific transcription factors that play an important role in plant growth and development, Although the GRF gene family has been identified in many species, a genome-wide analysis of this gene family in pineapple has not been reported.Results: In this study, 8 pineapple GRF genes (AcGRF) were identified and renamed according to their chromosomal locations.8 AcGRFs were divided into three main families and subgroups based on their structural and phylogenetic characteristics. Genomic collinearity analysis found that segmental duplication played a more important role in the expansion of the pineapple GRF gene family. GRF gene collinearity analysis and phylogenetic analysis provide deeper insights into the evolutionary characteristics of pineapple GRF genes. Transcriptome data and real-time quantitative PCR analysis revealed AcGRF gene expression patterns in various tissues and responses to different abiotic stresses and hormonal treatments.Conclusions: In this study, 8 GRF genes were identified in pineapple, and their coding gene structures, evolutionary characteristics, and expression patterns were analyzed. This systematic analysis provides a basis for further identification of pineapple GRF gene function.

以不同菠萝种质的顶芽、花和果实为材料,通过组织切片和解剖观察果眼形成过程,测定和分析果眼相关组织器官的动态变化.菠萝果眼形成过程分为花腔分化、花腔发育和果眼发育3个阶段.花腔是果眼的早期形态,其分化和发育过程约需70 d;而坐果标志着果眼发育阶段的起始.花腔形态分化是从花萼分化开始,至花盘(含花托和子房)分化结束;催花后14d顶芽基部首先出现花萼原基分化,自下而上,35 d时花腔分化结束,花序顶部花腔形态分化完成时间比基部迟7d左右.形态分化完成后进入花腔发育阶段,催花36～42 d是花腔膨大高峰期,此时深、浅果眼品种的花腔深度开始出现显著差异,此后膨大逐渐减缓;品种间花盘的绝对生长量相差不大,花腔的加深主要取决于花萼的生长.坐果后进入果眼发育期,随着果实迅速膨大,萼筒背腹面生长不均衡,宿萼向内弯曲;但宿萼弯曲速度和生长停止时间因品种而异,浅果眼品种'MD-2'宿萼伸长生长量小、内弯迅速,深果眼品种'金筒'宿萼则生长量较大、内弯缓慢.果眼加深主要在坐果后14d内,坐果约70 d时果眼的形态和大小已不再变化.根据成熟果实中部果眼的深浅,可将菠萝种质划分为浅(果眼深＜ 0.9 cm)、中(果眼深0.9～1.2 cm)、深(果眼深＞ 1.2 cm)3个类型;不同类型品种间花盘深度没有明显差异(约0.29 cm),果眼深浅差异主要由宿萼高度的不同引起,而宿萼的弯曲程度和生长量是导致类型间宿萼高度及小果凸出度出现差异的主要原因.因此,菠萝果眼形成始于花芽分化,花萼生长发育对果眼的形态和深浅产生重大影响,品种间果眼形态差异主要由坐果14 d内萼筒部背腹面生长量不均衡引起,而果眼深浅差异主要发生在花萼发育的前7d(催花36 ～ 42 d).

MYB proteins constitute one of the largest transcription factor families in plants, members of which are involved in various plant physiological and biochemical processes. Japanese plum (Prunus salicina) is one of the important stone fruit crops worldwide. To date, no comprehensive study of the MYB family in Japanese plum has been reported. In this study, we performed genome-wide analysis of MYB genes in Japanese plum including the phylogeny, gene structures, protein motifs, chromosomal locations, collinearity and expression patterns analysis. A total of 96 Japanese plum R2R3-MYB (PsMYB) genes were characterized and distributed on 8 chromosomes at various densities. Collinearity analysis indicated that the segmental duplication events played a crucial role in the expansion of PsMYB genes, and the interspecies synteny analysis revealed the orthologous gene pairs between Japanese plum and other four selected Rosaceae species. The 96 PsMYB genes could be classified into 27 subgroups based on phylogenetic topology, as supported by the conserved gene structures and motif compositions. Further comparative phylogenetic analysis revealed the functional divergence of MYB gene family during evolution, and three subgroups which included only Rasaceae MYB genes were identified. Expression analysis revealed the distinct expression profiles of the PsMYB genes, and further functional predictions found some of them might be associated with the plum fruit quality traits. Our researches provide a global insight into the organization, phylogeny, evolution and expression patterns of the PsMYB genes, and contribute to the greater understanding of their functional roles in Japanese plum.