Changes in mRNA and Protein during Ripening in Apple Fruit (Malus domestica Borkh. cv Golden Delicious)

Poly(A)⁺ RNA was extracted from cortical tissue of apple fruit (Malus domestica Borkh. cv Golden Delicious), and in vitro translation products were analyzed by two-dimensional gel electrophoresis. As fruit internal ethylene concentration increased from a basal level of 0.0 to 0.1 microliter per liter to 1 to 5 microliters/liter, substantial changes in the pattern of in vitro translation products were observed. More subtle changes were observed as fruit continued to ripen and internal ethylene concentration increased to 80 to 100 microliters/liter. Overall, the levels of at least six mRNAs were found to increase, while one mRNA decreased. Analysis of proteins extracted from ripening fruit indicated that the level of at least three proteins increased with ripening.     

Estimation of Provisional Seed Viability Constants for Apple (Malus domestica Borkh. cv. Greensleeves)

Estimates of viability constants have been calculated for apple(cv. Greensleeves) seeds, stored hermetically in a range ofenvironments. The constants allow reasonable prediction of seedstorage life (orthodox), at least in the short and medium term. Apple, Malus domestica Borkh. cv. Greensleeves, seed storage, viability constants, influence of seed moisture content and temperature     

Cytohistochemical Analysis of Malus domestica Borkh. Seeds from Shedding and Nonshedding Fruits

A histological, cytochemical, and ultrastructural investigation of seeds of control (nonshedding) and shedding fruits of Malus domestica Borkh. showed differences in the pattern of nutrient distribution. The kind and amount of storage compounds in the two seeds also differed. Protein bodies and starch were abundant in the control seeds and nearly absent in the seeds of shedding fruit. In the latter, there was a great abundance of phenols that exhibited a specific distribution in different tissues of the chalazal region. A cuticle was present on the inner side of the inner integument of the seeds of both control and shedding fruits. This cuticle was interrupted in the chalaza and formed a pathway for nutrient translocation, what we termed the "window." Cell wall changes observed in the chalazal window were probably associated with the different distribution pattern of storage compounds and with the control of nutrient routing. The delayed and variable development of the embryos of seeds in shed fruits may be related to both the altered pattern of storage substances and their translocation to the embryo.     

Protein Changes during the Stratification of Malus domestica Borkh. Seed

Apple seeds (Malus domestica Borkh. cv Golden Delicious) were stratified at 5 and 15°C for various lengths, weighed, and soluble protein of axis and cotyledon tissue was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Only seeds treated at 5°C germinated; seeds treated at 15°C did not germinate. Optimal germination required 63 days of stratification. Excised embryos required less stratification time for germination than intact seeds. When stratification was less than 35 days, the resulting seedlings from 5°C stratified embryos were dwarfed and epinastic. After 63 days of stratification, axes from 5 and 15°C treated intact seeds had increased in fresh weight by 72 and 28% (w/w), respectively. The dry weights of the axes did not change significantly and both fresh and dry weights of cotyledons remained unchanged during stratification. Total soluble protein in axes and cotyledons changed very little during stratification. However, axis polypeptide profiles changed. Most obvious was the occurrence of a new polypeptide and the increase of four other clearly identifiable polypeptides during 5°C treatment. The levels of the five most predominant axis proteins decreased at the same time. We observed no changes in the profiles of soluble cotyledon proteins. Control seeds kept at −10°C showed none of the reported changes.     

Differential Chloroplast Proteomics of Temperature Adaptation in Apple (Malus x domestica Borkh.) Microshoots

Temperature stress is one of the most common external factors that plants have to adapt to. Accordingly, plants have developed several adaptation mechanisms to deal with temperature stress. Chloroplasts are one of the organelles that are responsible for the sensing of the temperature signal and triggering a response. Here, chloroplasts are purified from low temperature (4° C), control (22° C) and high temperature (30° C) grown Malus x domestica microshoots. The purity of the chloroplast fractions is evaluated by marker proteins, as well as by using in silico subcellular localization predictions. The proteins are digested using filter‐aided sample processing and analyzed using nano‐LC MS/MS. 733 proteins are observed corresponding to published Malus x domestica gene models and 16 chloroplast genome ‐encoded proteins in the chloroplast preparates. In ANOVA, 56 proteins are found to be significantly differentially abundant (p < 0.01) between chloroplasts isolated from plants grown in different conditions. The differentially abundant proteins are involved in protein digestion, cytoskeleton structure, cellular redox state and photosynthesis, or have protective functions. Additionally, a putative chloroplastic aquaporin is observed. Data are available via ProteomeXchange with identifier PXD014212.     

1-甲基环丙烯(1-MCP)对'嘎拉'苹果贮藏期间果肉细胞结构的影响

在室温[(25±1)℃]条件下观察1-甲基环丙烯(1-MCP)影响下‘嘎拉’苹果采后果肉细胞结构变化的结果表明,随着贮藏时间的延长,未作1-MCP处理的果实果肉细胞逐渐失去张力,细胞壁皱褶,中胶层逐渐降解,继而出现胞间裂痕,细胞间隙逐渐增大,细胞壁纤维松散,细胞器逐渐空泡化等现象;1-MCP显著抑制果肉细胞的结构损伤,最终减缓果实的软化。     

Adaptations of Malus domestica Borkh. (Rosaceae) Fruits Grown at Different Altitudes

Russian Journal of Plant Physiology - Cytophysiological adaptive features of apple fruits (Malus domestica Borkh.) were examined as a function of growth altitude—300, 500, 700, and 1200 m...     

苹果果实糖积累特性与品质形成的关系

以'富士'和'国光'苹果为研究对象,对其果实发育过程中糖含量及其代谢关键酶活性的变化进行测定分析,以揭示糖分积累代谢特性对果实品质形成的影响.结果表明:(1)'富士'和'国光'均为己糖积累型果实, '富士'果实以积累果糖最多,果糖/葡萄糖(F/G)值为1.56,而'国光'以积累葡萄糖最多,F/G值仅为0.68;蔗糖在两品种中含量和所占比例均很低,在近成熟期'富士'高于'国光'.(2)'富士'果实蔗糖磷酸合成酶(SPS)和蔗糖合成酶(SS)活性均随果实糖的累积量增加而显著升高,酸性转化酶(AI)活性也渐趋升高,而中性转化酶(NI)活性波动不大,且其糖累积与AI和SPS活性相关性最大,而与NI相关性不大,SS的作用主要表现在发育后期;在 '国光'果实糖积累过程中SPS起主导作用,SS和NI的作用主要表现在发育前期,而AI的作用不大.(3)'富士'和'国光'果实淀粉含量变化趋势相同,在淀粉积累高峰之后,'富士'果实淀粉降解速度更快,其淀粉含量迅速下降且低于'国光',此时其相应淀粉酶活性也高于'国光'.研究发现,'富士'和'国光'果实糖积累和淀粉代谢均存在显著差异,从而直接或间接地影响着果实糖代谢过程,进而导致果实品质的显著差异.     

A Positive Root-sourced Signal as an Indicator of Soil Drying in Apple, Malus x domestica Borkh.

Plants raised from shoot-tip cultures of apple (Malus x domesticaBorkh ) were grown in divided pots so that approximately halfthe root system could be exposed to soil drying whilst the remainderwas well watered. Water was withheld from half the root systemin this way for 24 d. During this time, the daily incrementin leaf area declined to 65% of that of control plants, whichhad all their roots in well watered soil Both leaf expansionand, more particularly, leaf initiation were inhibited. Waterloss per plant also fell to 70%% of the rate exhibited by controlplants. No significant differences were detected between theleaf water status of the partially dried plants and that ofthe well watered ones After this drying period, the half-dried plants were treatedduring the night of the 24th day as follows; one group had itsroots in dry soil rewatered, another had them excised, and athird continued half dry Both the rewatered group and the groupwith roots excised showed significant recoveries in leaf growthrates compared with the group kept half dry. The inhibition of leaf growth by drying soil is discussed withregard to root-to-shoot signalling The alleviation of this inhibitionby the excision of roots in dry soil, is taken as evidence ofa positive inhibitor, produced by drying roots, influencingshoot growth. Key words: Leaf growth, soil drying, root signals, Malus x domestica     

A Multidisciplinary Approach Providing New Insight into Fruit Flesh Browning Physiology in Apple (Malus x domestica Borkh.)

In terms of the quality of minimally processed fruit, flesh browning is fundamentally important in the development of an aesthetically unpleasant appearance, with consequent off-flavours. The development of browning depends on the enzymatic action of the polyphenol oxidase (PPO). In the ‘Golden Delicious’ apple genome ten PPO genes were initially identified and located on three main chromosomes (2, 5 and 10). Of these genes, one element in particular, here called Md-PPO, located on chromosome 10, was further investigated and genetically mapped in two apple progenies (‘Fuji x Pink Lady’ and ‘Golden Delicious x Braeburn’). Both linkage maps, made up of 481 and 608 markers respectively, were then employed to find QTL regions associated with fruit flesh browning, allowing the detection of 25 QTLs related to several browning parameters. These were distributed over six linkage groups with LOD values spanning from 3.08 to 4.99 and showed a rate of phenotypic variance from 26.1 to 38.6%. Anchoring of these intervals to the apple genome led to the identification of several genes involved in polyphenol synthesis and cell wall metabolism. Finally, the expression profile of two specific candidate genes, up and downstream of the polyphenolic pathway, namely phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO), provided insight into flesh browning physiology. Md-PPO was further analyzed and two haplotypes were characterised and associated with fruit flesh browning in apple.     

Polyamines and Nitric Oxide Link in Regulation of Dormancy Removal and Germination of Apple (Malus domestica Borkh.) Embryos

Polyamines (PAs) belong to plant growth regulators and in complex with classical phytohormones take part in regulation of seed dormancy and germination. Although the impact of reactive oxygen (ROS) and nitrogen (RNS) species on seed germination is well described, the cross talk of PAs with ROS/RNS has never been analyzed. Due to the close connection of PAs and ethylene biosynthetic pathways to arginine (Arg)-dependent NO biosynthesis we investigated production of nitric oxide (NO), peroxynitrite (ONOO^?) and the level of O ₂ ^?? or H₂O₂ in apple embryos, germination of which was PA regulated. PAs: putrescine (Put) and spermidine (Spd) in contrast to spermine (Spm) stimulated germination of apple embryos. Among amino acids, stimulation of germination was observed in Arg and ornithine (Orn) only. Dormancy removal of embryos by PAs was associated with increased accumulation of H₂O₂ and O ₂ ^?? in embryonic axes. At the same stage of completion of sensu stricto germination the stimulatory effect of PAs (Put and Spd) and amino acids, mainly Arg and Orn, was accompanied by enhanced NO and ONOO^? production in embryonic axis. The beneficial effect of PAs (Put and Spd) and their precursors on germination of apple embryos was removed by NO scavenging, suggesting a crucial role of NO in termination of embryo germination and radicle growth. Moreover, activity of polyamine oxidase in embryo axes was greatly enhanced by embryo fumigation with NO. Our data demonstrate the interplay of RNS/ROS with PAs and point to NO action as an integrator of endogenous signals activating germination.     

Characterisation of the DELLA subfamily in apple (Malus x domestica Borkh.)

The hormone gibberellic acid (GA) regulates growth and development throughout the plant life cycle. DELLA proteins are key components of the GA signalling pathway and act to repress GA responses. The “DELLA” amino acid motif is highly conserved among diverse species and is essential for GA-induced destruction of DELLA proteins, which relieves repression. Six genes encoding the DELLA motif were identified within an apple expressed sequence tag (EST) database. Full-length cDNA clones were obtained by RACE and these were designated MdRGL1a/b, MdRGL2a/b, and MdRGL3a/b. Sequence alignment of the predicted proteins indicates that the MdDELLAs are 37–93% homologous to one another and 44–65% to the Arabidopsis DELLAs. The MdDELLAs cluster into three pairs, which reflect the presumed allopolyploid origins of the Maloideae. Expression analysis using quantitative real-time PCR indicates that all three pairs of MdDELLA mRNAs are expressed at the highest levels in summer arrested shoot tips and in autumn vegetative buds. Transgenic Arabidopsis expressing MdRGL2a have smaller leaves and shorter stems, take longer to flower in short days, and exhibit a reduced response to exogenous GA₃, indicating significant conservation of gene function between DELLA proteins from apple and Arabidopsis. Electronic supplementary material Supplementary material is available for this article at and is accessible for authorized users.     

Microsatellite markers spanning the apple (Malus x domestica Borkh.) genome

A new set of 148 apple microsatellite markers has been developed and mapped on the apple reference linkage map Fiesta x Discovery. One-hundred and seventeen markers were developed from genomic libraries enriched with the repeats GA, GT, AAG, AAC and ATC; 31 were developed from EST sequences. Markers derived from sequences containing dinucleotide repeats were generally more polymorphic than sequences containing trinucleotide repeats. Additional eight SSRs from published apple, pear, and Sorbus torminalis SSRs, whose position on the apple genome was unknown, have also been mapped. The transferability of SSRs across Maloideae species resulted in being efficient with 41% of the markers successfully transferred. For all 156 SSRs, the primer sequences, repeat type, map position, and quality of the amplification products are reported. Also presented are allele sizes, ranges, and number of SSRs found in a set of nine cultivars. All this information and those of the previous CH-SSR series can be searched at the apple SSR database () to which updates and comments can be added. A large number of apple ESTs containing SSR repeats are available and should be used for the development of new apple SSRs. The apple SSR database is also meant to become an international platform for coordinating this effort. The increased coverage of the apple genome with SSRs allowed the selection of a set of 86 reliable, highly polymorphic, and overall the apple genome well-scattered SSRs. These SSRs cover about 85% of the genome with an average distance of one marker per 15 cM.E. Silfverberg-Dilworth and C. L. Matasci contributed equally to this work.