Young Fruit Research Articles

Lasiodiplodia theobromae (Pat.) Griffon & Maul [(sin.) Botryodiplodia theobromae Pat] en el cultivo de cacao: síntomas, ciclo biológico y estrategias de manejo

Throughout history, the cocoa crop (Theobroma cacao L.) has been affected by countless diseases, some of these caused by Lasiodiplodia theobromae (Pat.) Griffon & Maul. Although three Lasiodiplodia species have been reported affecting cocoa plants, L. theobromae is the most studied species both in cocoa and other crops. In recent years this phytopathogen has been gaining importance. In cocoa, L. theobromae can survive in soil and culture remains in the form of pycnidia and chlamydospores, spreading by different factors until reaching the plant tissues, remaining there as an endophyte. The pathogenic fungus can cause young twigs death (a characteristic symptom found in field conditions), fruits rot and mummification, and even vascular dieback. In general, the management of pathogens of the Botryosphaeriaceae family is complex, even more so when the pathogen is already present in the crop area. However, there are genetic, cultural, biological, chemical control measures, among others, that could be integrated and used in cocoa crops. As there is little information about L. theobromae in cocoa crops, we believe that this review will be very helpful for both technicians and researchers.

The MADS-box gene FveSEP3 plays essential roles in flower organogenesis and fruit development in woodland strawberry

Flower and fruit development are two key steps for plant reproduction. The ABCE model for flower development has been well established in model plant species; however, the functions of ABCE genes in fruit crops are less understood. In this work, we identified an EMS mutant named R27 in woodland strawberry (Fragaria vesca), showing the conversion of petals, stamens, and carpels to sepaloid organs in a semidominant inheritance fashion. Mapping by sequencing revealed that the class E gene homolog FveSEP3 (FvH4_4g23530) possessed the causative mutation in R27 due to a G to E amino acid change in the conserved MADS domain. Additional fvesep3CR mutants generated by CRISPR/Cas9 displayed similar phenotypes to fvesep3-R27. Overexpressing wild-type or mutated FveSEP3 in Arabidopsis suggested that the mutation in R27 might cause a dominant-negative effect. Further analyses indicated that FveSEP3 physically interacted with each of the ABCE proteins in strawberry. Moreover, both R27 and fvesep3CR mutants exhibited parthenocarpic fruit growth and delayed fruit ripening. Transcriptome analysis revealed that both common and specific differentially expressed genes were identified in young fruit at 6–7 days post anthesis (DPA) of fvesep3 and pollinated wild type when compared to unpollinated wild type, especially those in the auxin pathway, a key hormone regulating fruit set in strawberry. Together, we provided compelling evidence that FveSEP3 plays predominant E functions compared to other E gene homologs in flower development and that FveSEP3 represses fruit growth in the absence of pollination and promotes fruit ripening in strawberry.

Preliminary assessment of ironwood (Eusideroxylon zwageri Teijsm. & Binnend.) stand on the KPPN Bulian of the District VIII of PT. Wirakarya Sakti, Jambi as seed source candidate

Ironwood (Eusideroxylon zwageri) is one of Indonesia’s most economically valuable timber tree species and was listed as Vulnerable in 1998 by the IUCN. To support conservation activities and establish E. zwageri’s plantation, good quality planting stocks should be collected from specific seed sources. Currently, there is only one ironwood seed source in Sumatra that has been registered. This study aimed to assess the potential for an ironwood stand on the KPPN Bulian of the District VIII of PT. Wirakarya Sakti is to be proposed as a seed source. The assessment was conducted on July 2020 by a 100% inventory of ironwood trees in the area of 43 ha. Every individual tree and copy of ironwood was measured for its stem diameter and tree height and observed for its health, flowers, fruits, and seedlings in the ground. In total, 1,029 individual trees, copies and seedlings were recorded. Among them, 116 trees were found to have young fruits and seedlings emergence in the forest floor. Generally, the ironwood stand is sound and meets the criteria to be registered as an identified seed stand of ironwood.

Occurrence of Canker and Wood Rot Pathogens on Stone Fruit Propagation Material and Nursery Trees in the Western Cape of South Africa.

Dieback and canker of young stone fruit trees can cause suboptimal growth and even death under severe conditions. One source of inoculum of canker pathogens could be through nursery trees harboring latent infections that would not be visible to inspections done according to the deciduous fruit scheme. The objectives of this study were to identify the canker and wood rot fungal pathogens present in nursery stone fruit trees as well as in propagation material and to evaluate their pathogenicity. Isolations were made from scion and rootstock propagation material and from certified nursery stone fruit trees. The plant material sampled did not have any external symptoms. The certified nursery trees when cross-sectioned displayed brown discoloration from the pruning wound, the bud union, and often the crown. Fungal species isolated were identified by sequencing of the relevant barcoding genes and phylogenetic analyses thereof. Canker- and wood rot-associated fungi were identified. Buds used for budding had low levels of infection, with 1.2% of dormant buds infected and 0.4% of green buds infected. The dormant rootstock shoots had a canker pathogen incidence of 6.2% before they were planted in the nursery fields and increased inasmuch as the ungrafted, rooted rootstock plants had 11.1% infection with canker and wood rot pathogens. Out of 1,080 nursery trees, the canker- and wood rot-associated fungi infected 21.8% of trees. The canker-causing pathogens that were isolated the most were Cadophora luteo-olivacea and Diplodia seriata. A low incidence of wood rot fungi was found, with only 1.5% of nursery trees infected. In total, 26 new reports of fungal species on stone fruit in South Africa were made. Of these, 22 have not been found on stone fruit worldwide. The pathogenicity trials' results confirmed the pathogenic status of these newly reported species. All of the isolates tested formed lesions significantly longer than the control, 4 months after wound inoculation of 2-year-old shoots of two plum orchards. Lasiodiplodia theobromae was the most virulent species on both plum cultivars. The results of this research showed that nursery stone fruit trees and propagation material can harbor latent infections. Different management practices need to be evaluated to prevent these infections to ensure healthier stone fruit nursery trees.

Alternaria alternata causing brown spot on kiwiberry (Actinidia arguta) in China

Kiwiberry (Actinidia arguta), originating from northeast Asia, is a new fruit product. Since 2018, fruits of kiwiberry showing brown spots were observed in orchards of Zhejiang Province, China. Disease symptoms started from the initial stage of fruit development. The brown spots on young fruits extended as the fruits developed. The fungus strain isolated from the affected fruits was preliminarily identified as Alternaria species according to morphological characteristics. Further molecular identification based on a multi-locus phylogenetic analysis comprised of partial sequences of internal transcribed spacer (ITS) rDNA region, endopolygalacturonase (endoPG) gene, major allergen (Alta1) gene, and 28S ribosomal RNA (LSU) gene verified that the fungus is Alternaria alternata. The pathogenicity of the isolated fungus was confirmed by artificial inoculation. The present identification constitutes the first report of A. alternata as the causal agent of brown spot on kiwiberry in China.

Tomato Young Fruits Detection Method under Near Color Background Based on Improved Faster R-CNN with Attention Mechanism

The information of tomato young fruits acquisition has an important impact on monitoring fruit growth, early control of pests and diseases and yield estimation. It is of great significance for timely removing young fruits with abnormal growth status, improving the fruits quality, and maintaining high and stable yields. Tomato young fruits are similar in color to the stems and leaves, and there are interference factors, such as fruits overlap, stems and leaves occlusion, and light influence. In order to improve the detection accuracy and efficiency of tomato young fruits, this paper proposes a method for detecting tomato young fruits with near color background based on improved Faster R-CNN with an attention mechanism. First, ResNet50 is used as the feature extraction backbone, and the feature map extracted is optimized through Convolutional Block Attention Module (CBAM). Then, Feature Pyramid Network (FPN) is used to integrate high-level semantic features into low-level detailed features to enhance the model sensitivity of scale. Finally, Soft Non-Maximum Suppression (Soft-NMS) is used to reduce the missed detection rate of overlapping fruits. The results show that the mean Average Precision (mAP) of the proposed method reaches 98.46%, and the average detection time per image is only 0.084 s, which can achieve the real-time and accurate detection of tomato young fruits. The research shows that the method in this paper can efficiently identify tomato young fruits, and provides a better solution for the detection of fruits with near color background.

Analysis of Light-Independent Anthocyanin Accumulation in Mango (Mangifera indica L.)

Light dependent anthocyanin accumulation contributes to the red pigmentation of the fruit skin of mango (Mangifera indica L.). Light-independent pigmentation has also been reported, but remains poorly characterized. In this study, the pigmentation patterns in the skin of two red mango cultivars, ‘Ruby’ and ‘Sensation’, were evaluated. Metabolomic profiling revealed that quercetin-3-O-glucoside, cyanidin-3-O-galactoside, procyanidin B1, and procyanidin B3 are the predominant flavonoid compounds in the skin of ‘Ruby’ and ‘Sensation’ fruit. Young fruit skin mainly accumulates flavonol and proanthocyanidin, while anthocyanin is mainly accumulated in the skin of mature fruit. Bagging treatment inhibited the biosynthesis of flovonol and anthocyanin, but promoted the accumulation of proanthocyanidin. Compared with ‘Sensation’, matured ‘Ruby’ fruit skin showed light red pigmentation at 120 days after full bloom (DAFB), showing a light-independent anthocyanin accumulation pattern. However, the increase of anthocyanin concentration, and the expression of key anthocyanin structural and regulatory genes MiUFGT1, MiUFGT3, and MiMYB1 in the skin of bagged ‘Ruby’ fruit versus ‘Sensation’ at 120 DAFB was very limited. There was no mutation in the crucial elements of MiMYB1 promoter between ‘Ruby’ and ‘Sensation’. We hypothesize that the light-independent anthocyanin accumulation in the skin of mature ‘Ruby’ fruit is regulated by plant hormones, and that ‘Ruby’ can be used for breeding of new more easily pigmented red mango cultivars.

Effectiveness of fungal, bacterial and yeast antagonists for management of mango anthracnose (Colletotrichum gloeosporioides)

BackgroundMango anthracnose, caused by Colletotrichum gloeosporioides, is one of the most important diseases of mango crop. It mainly attacks leaves, flowers, young fruits and twigs and also appears as a post-harvest disease of ripened fruits. Application of bio-control agents has huge potential in plant disease management. The goal of the present research was to establish the potential of individual and combined bio-control agents for the management of mango anthracnose under in vitro and under field conditions.ResultsThe antagonistic reaction of six fungi, six bacteria and nine yeasts against C. gloeosporioides on potato dextrose agar medium and malt extract agar medium was observed among which Trichoderma harzianum was found to be the most efficient with 89.26% mycelial growth inhibition. Evaluation of bio-control agents against anthracnose disease development on mango fruit revealed that dip treatment of mango fruits in spore suspension (1.2 × 104 cfu/ml) of T. harzianum for 5 min was the most effective and provided disease control to the tune of 81.67%. Combined application of effective bio-control agents as a post-harvest fruit dip treatment was also evaluated against the mango anthracnose on mango fruits, where the treatment of T. harzianum + Pichia anomala was very effective with 93.39% disease control. Under field conditions, three consecutive sprays of T. harzianum, starting with the initiation of disease on leaves, followed by other two sprays at an interval of 15 days during 2015 and 2016 were found the best for the management of mango anthracnose disease both on leaves and on fruits at two locations.ConclusionsThe combined and individual applications of bio-control agents, viz.T. harzianum, Bacillus subtilis and P. anomala, through foliar spray or by fruit dip had the potential to control mango anthracnose. The bio-formulations of these bio-control agents had the potential to replace chemical fungicides and also protect the natural environment, thus playing a significant role in integrated disease management.

Carboxymethyl cellulose from Young Palmyra palm fruit husk: Synthesis, characterization, and film properties

A young Palmyra palm fruit husk, an agricultural by-product after removing sweet jelly seed, was used as starting material for carboxymethyl cellulose (CMC) synthesis. Significant increases for percent yield (101.35–125.72%), degree of substitution (DS: 0.19–0.58), and solubility (10.04–83.58%) were observed when sodium hydroxide (NaOH) level increased (30–60%, w/v) (P < 0.05). The crystallinity of the carboxymethyl cellulose synthesized from young Palmyra palm fruit husk (CMCy) was decreased as compared to cellulose. The CMCy films showed a significant difference in the film properties, compared to the commercial CMC (CMCc) film (P < 0.05). The synthesized CMCy films appeared light yellow with a rough surface, while the CMCc film had colorless and transparent. However, the synthesized CMCy films showed greater thickness than the CMCc film, but less tensile strength and water vapor permeability (P < 0.05). According to these findings, young Palmyra palm fruit husk had the potential to produce CMC and could be applied in food packaging.

ANALYSIS OF VITAMIN C AND B1 LEVELS IN SENDUDUK FRUIT (Melastoma malabathricum L.) USING UV-VIS SPECTROPHOTOMETRY METHOD

The fruit of "senduduk" contains a variety of nutrients and vitamins including vitamin C and B1. This study aims to determine the levels of vitamins C and B1 in young and ripe senduduk fruit that grows in coastal areas and in the mountains. The sample of the fruit was extracted with water. The absorbance of the extract of the fruit was then measured using UV-Vis spectrophotometry for vitamin C at a wavelength of 250 nm, while for vitamin B1 was measured at 420 nm. The results showed that vitamin C levels were (G1 = 0.34; G2 = 0.29%; P1 = 0.35; and P2 = 0.31)%, vitamin B1 was (G1 = 0.21; G2 = 0, 10%; P1 = 0.28; and P2 = 0.18)%. The results of the study can be concluded that there is a significant difference in vitamin C levels between young and old fruit, but it is not significantly different for the difference in the place of growth. There is a significant difference in vitamin B1 levels between young and ripe senseng fruit.

Effect of Special Compound Microbial Fertilizer on Growth and Quality of Walnut

On the basis of the research on the site condition of mineral yellow soil in the early stage, the purple soil walnut planting area in Xide County of Liangshan Prefecture was selected to carry out the fertilizer contrast experimen, in order to put forward reasonable fertilization suggestions for walnut planting in the purple soil widely distributed area. The 4-year-old shuoxing saplings and 10-year-old hanging fruit trees were selected as the experimental materials, and four treatments (T1: no fertilization, T2: application of common compound fertilizer, T3: application of special inorganic fertilizer, T4: application of compound microbial fertilizer) were set up to explore the effects of special compound microbial fertilizer on the plant height, fruit yield, quality and economic benefits of young trees. The results showed that the application of special compound microbial fertilizer could increase the height and fruit yield of young walnut trees. The growth of young walnut tree height and fruit yield in purple soil was higher than that in mineral yellow soil. The application of compound fertilizer was 38.03% higher than that of no fertilizer, 27.27% higher than that of common compound fertilizer and 10.11% higher than that of inorganic special fertilizer. The yield of walnut fruit increased by 44.56% and 28.04% compared with no fertilizer and common compound fertilizer, and the transverse diameter, weight, kernel yield, fat content and protein content of walnut fruit increased by 10.99%, 14.89%, 10.31%, 8.09% and 7.27%, respectively.

Molecular Identification and Antifungal Properties of Four Thaumatin-like Proteins in Spruce (Picea likiangensis)

Thaumatin-like proteins (TLPs) are involved in the plant defense response against pathogens, and most of them exhibit antifungal activity. However, the role of TLPs in pathogen-induced defense responses in spruce is not fully understood. In this study, four TLP genes encoding thaumatin-like protein, designated as PlTLP1–4, were isolated and identified from Picea likiangensis needles. Sequence analysis showed that PlTLP1, PlTLP3, and PlTLP4 contained 16 conserved cysteine residues, while PlTLP2 had only 10 conserved cysteine residues. qPCR analysis showed that PlTLPs were expressed in all tissues tested, PlTLP1, PlTLP3, and PlTLP4 had the highest expression levels in young fruits, while PlTLP2 had the highest expression levels in roots. In addition, the expression levels of four PlTLPs were significantly upregulated during infection by Lophodermium piceae. Four recombinant PlTLPs expressed in Escherichia coli exhibited obvious β-1,3-glucanase activity. The antifungal activity assay showed that four recombinant PlTLPs had significant inhibitory effects on the mycelial growth of L. piceae, Fusarium proliferatum, Botrytis cinerea, and Roussoella doimaesalongensis. Microscopic observation revealed that the recombinant PlTLP1–4 induced the morphological changes of the mycelia of L. piceae, and the recombinant PlTLP2 and PlTLP3 induced the morphological changes of the mycelia of F. proliferatum and R. doimaesalongensis, while all the recombinant PlTLPs had no obvious negative effect on the morphology of B. cinerea mycelium. These results suggest that PlTLP genes may play an important role in the defense response of P. likiangensis against L. piceae invasion.

Effects of intercropping with Solanum photeinocarpum and its post-grafting generations on cadmium accumulation in loquat (Eriobotrya japonica)

Cadmium (Cd) contamination of orchard soils is a global problem that has been increasing. To decrease the Cd accumulation in fruits, intercropping the orchard crops with hyperaccumulator plants has been used for soil remediation. A pot and a field experiment were conducted to study the effects of intercropping the potential Cd-hyperaccumulator Solanum photeinocarpum and its post-grafting generations with loquat (Eriobotrya japonica) on the growth and Cd uptake of these two plant species. In the pot experiment, intercropping improved the biomass, Cd content, Cd extraction, and root-to-shoot Cd translocation in both species. Intercropping increased the DNA methylation levels, antioxidant enzyme activity, and soluble protein content of loquat seedlings. These results indicate that intercropping could improve the phytoremediation of S. photeinocarpum and its post-grafting generations and increase the Cd uptake in loquat seedlings. In the field experiment, intercropping increased the Cd contents in the old branches, while it decreased that in the young branches and fruits of loquat. These findings indicate that intercropping could increase the Cd uptake in old tissues but reduce the Cd uptake in young tissues and fruits of loquat. So, intercropping loquat with S. photeinocarpum and its post-grafting generations could be used in Cd-contaminated orchards.

Herbalogical study on historical evolution of collection, processing and efficacy of Citri Exocarpium Rubrum and Citri Grandis Exocarpium

In ancient times, the original plants of Citri Exocarpium Rubrum and Citri Grandis Exocarpium had experienced succession and change, including tangerine(Citrus reticulata), pomelo(C. grandis), and Huazhou pomelo(C. grandis 'Tomentosa'), a specific cultivar of C. grandis produced in Huazhou, Guangdong. Before the Qing Dynasty, tangerine was the main original plant, while Huazhou pomelo came to the fore in the Qing Dynasty. In the 1950 s and 1960 s, the producing area of Huazhou pomelo was destroyed, and thus it had to be supplemented with pomelo. From then on, C. grandis 'Tomentosa' and C. grandis were both listed as the original plants of Citri Grandis Exocarpium in the Chinese Pharmacopoeia. This paper reviewed the historical evolution of the collection, processing, and efficacy of Citri Exocarpium Rubrum and Citri Grandis Exocarpium. The research showed that:(1)The harvest time of the original plants of Citri Grandis Exocarpium and Citri Grandis Exocarpium had changed from maturity to immaturity. The collection and processing of Citri Exocarpium Rubrum was first recorded in the Illustrated Classics of Materia Medica in the Song Dynasty. During the Ming and Qing Dynasties, the mesocarp of Citri Exocarpium Rubrum needed to be removed completely, and Citri Grandis Exocarpium from C. grandis 'Tomentosa' was processed into different specifications such as seven-piece, five-piece, and single piece. Furthermore, processed young fruits of Huazhou pomelo appeared.(2)Citri Exocarpium Rubrum and Citri Grandis Exocarpium were processed with carp skin for the first time in the Master Lei's Discourse on Medicinal Processing. It was suggested that carp skin might be helpful for eliminating bones stuck in throat. During the Song, Jin, and Yuan Dynasties, some other processing methods such as ba-king, stir-frying, and salt-processing appeared. Honey, soil, ginger juice, and alum were firstly used as adjuvants for the processing in the Ming and Qing Dynasties. Citri Exocarpium Rubrum was mainly prepared with salt in order to improve the effect of lowering Qi, while it was unnecessary for Citri Grandis Exocarpium from C. grandis 'Tomentosa' because of its obvious effect of lowering Qi and eliminating phlegm. The stir-frying and honey-frying methods helped reduce the strong effect of Citri Grandis Exocarpium from C. grandis 'Tomentosa'.(3)According to the application of Citri Exocarpium Rubrum and Citri Grandis Exocarpium in history, their medicinal use began in Han and Tang Dynasties, developed in Song, Jin, and Yuan Dynasties, and matured in Ming and Qing Dynasties. Citri Grandis Exocarpium from C. grandis 'Tomentosa' was originally applied in Ming and Qing Dynasties, and it still plays an important in role treating COVID-19 nowadays. Moreover, Citri Grandis Exocarpium from C. grandis had cold medicinal property, while Citri Grandis Exocarpium from C. grandis 'Tomentosa' had warm medicinal property, and thus they should not be treated the same. At present, Huazhou pomelo has a certain production scale. Therefore, it is recommended that in the next edition of Chinese Pharmacopoeia, only C. grandis 'Tomentosa' should be included as the original plant of Citri Grandis Exocarpium, and C. grandis should be deleted. The results are conducive to the further development and utilization of Citri Exocarpium Rubrum and Citri Grandis Exocarpium, and support the rational use of Citri Grandis Exocarpium and its processed products.

Tocochromanols and Chlorophylls Accumulation in Young Pomelo (Citrus maxima) during Early Fruit Development.

Pomelo is an important cultivar of the genus Citrus that contains a variety of beneficial nutrients, and its young fruit is an agricultural by-product that is currently not fully utilized because it is often thrown away during cultivation and management. In this study, the dynamics of tocochromanol during young pomelo development were investigated by measuring chlorophyll content, tocochromanol accumulation, and expression levels of related genes during early fruit development. The results showed that chlorophyll content decreased overall during these four developmental stages and had some synergism with tocochromanol. Four tocochromanol components were detected in pomelo of both genotypes, and α-tocopherol was the main component. The tocochromanol content of honey pomelo was highest in the first period, reaching 70 ± 5 μg/g in dry weight (DW), and golden pomelo peaked in the second period at 86.10 ± 0.18 μg/g DW, with an overall decreasing trend in both genotypes. The different gene expression patterns of the tocochromanol biosynthesis pathway could partially explain the changes in these components and further elucidate the regulatory mechanisms of tocochromanol accumulation during early fruit development. As a natural product, young pomelo fruit is an attractive source of tocochromanol and has potential application in industrial production. The results of this study may provide directions for the high additional value utilization of young pomelo fruit.

Distribution of Triterpenoids and Steroids in Developing Rugosa Rose (Rosarugosa Thunb.) Accessory Fruit.

Triterpenoids and steroids are considered to be important for the fruit quality and health-promoting properties for the consumers. The aim of the study was the determination of the changes in triterpenoid and steroid biosynthesis and the accumulation in hypanthium and achenes of rugosa rose (Rosa rugosa Thunb.) hip during fruit development and ripening at three different phenological stages (young fruits, fully developed unripe fruits, and matured fruits). Triterpenoids and steroids were also determined in the peel and the pulp of the matured hips. The obtained results indicated that the distribution of the analyzed compounds in different fruit tissues is a selective process. The increased rate of hydroxylation of triterpenoids, the deposition of hydroxylated acids in fruit surface layer, and the continuous biosynthesis of phytosterols in achenes versus its gradual repression in hypanthium accompanied by the accumulation of their biosynthetic intermediates and ketone derivatives seem to be characteristic metabolic features of maturation of rugosa rose accessory fruit. These observations, apart from providing the important data on metabolic modifications occurring in developing fruits, might have a practical application in defining fruit parts, particularly rich in bioactive constituents, to enable the development of novel functional products.

Evaluation of Carotenoids Accumulation and Biosynthesis in Two Genotypes of Pomelo (Citrus maxima) during Early Fruit Development.

Pomelo is rich in bioactive compounds (carotenoids, phenolics and essential oil) in the early stage of fruit development, but it is often wasted in the cultivation and management process. To gain an insight into the carotenoid metabolism pathway in pomelo, the carotenoid profiles and the expression patterns of carotenogenic genes were investigated in two genotypes of pomelo during early fruit development. The results showed that a higher carotenoid content was observed in honey pomelo as compared with golden pomelo, which may be related to different gene regulation mechanisms. Lutein, α-carotene, and β-carotene were the main carotenoids in pomelo young fruit, and lutein was the highest one. The accumulation of carotenoids during fruit early development in honey pomelo is related to the transcriptional regulation of ZISO and LUT5. In golden pomelo, the rate-limiting gene for carotenoids is PDS and ZDS. In addition, the expression of seven genes except CRTISO in honey pomelo was higher than that in golden pomelo. The results are helpful to further clarify the regulatory mechanism of carotenoid accumulation during early fruit development and provide a direction for the high-value utilization of young fruits in pomelo.

Pomegranate Fruit Growth and Skin Characteristics in Hot and Dry Climate.

Pomegranate (Punica granatum L.) fruit is well known for its health-beneficial metabolites. The pomegranate peel consists of an inner thick spongy white tissue, and an outer smooth skin layer that accumulates anthocyanins in red cultivars when ripe. The skin is made up of epidermis cells covered by a cuticle, the latter being the first target of cracking and russeting. The present study focuses on the effect of Israel’s hot and dry climate on pomegranate growth, to elucidate the derived effects on fruit skin characteristics and its putative resistance to the building pressure from fruit expansion. Experiments were conducted for four years, in four orchards located in different regions of the country, each with a different typical microclimate. Fruit-growth parameters were followed using remote-sensing tools, microscopic study, and mineral analysis of the skin, followed by determination of the peel’s elastic modulus. Fruit expanded in two phases: a short rapid phase followed by a gradual phase with a sigmoidal growth-rate pattern. Extreme hot and dry climate during the period of maximal growth rate was associated with restricted growth and a high proportion of small-size fruit. Anatomical study indicated that the skin of mature pomegranate fruit is made up of epidermal cells that are relatively flat and spaced apart, and is expected to be less durable against internal pressure. In contrast, skin of early immature fruit has two layers of dense and rounded epidermis, and is expected to be more resistant to cracking. Tensile strength studies confirmed this trend—skin of mature fruit had a lower elastic modulus than young fruit. However, restrained growth due to extreme environmental cues may result in better resistance of the mature pomegranate fruit to cracking, and in better skin quality and appearance, albeit small fruits. On the other hand, temperate climate at the beginning of the growth period, which allows high growth rate and high daily shrinkage, leads to pomegranate skin disorders.

Identification of apple TFL1-interacting proteins uncovers an expanded flowering network

MdTFL1, a floral repressor, forms protein complexes with several proteins and could compete with MdFT1 to regulate reproductive development in apple. Floral transition is a key developmental stage in the annual growth cycle of perennial fruit trees that directly determines the fruit development in the subsequent stage. FLOWERING LOCUS T (FT)/TERMINAL FLOWER1 (TFL1) family is known to play a vital regulatory role in plant growth and flowering. In apple, the two TFL1-like genes (MdTFL1-1 and MdTFL1-2) function as floral inhibitors; however, their mechanism of action is still largely unclear. This study aimed to functionally validate MdTFL1 and probe into its mechanism of action in apple. MdTFL1-1 and MdTFL1-2 were expressed mainly in stem and apical buds of vegetative shoots, with little expression in flower buds and young fruit. Expression of MdTFL1-1 and MdTFL1-2 rapidly decreased during floral induction. On the other hand, transgenic Arabidopsis, which ectopically expressed MdTFL1-1 or MdTFL1-2, flowered later than wild-type plants; demonstrating their in planta capability to function redundantly as flower repressors. Furthermore, we identified hundreds of novel interaction proteins of the two apple MdTFL1 proteins using yeast two-hybrid screens. Independent experiments for several proteins confirmed the yeast two-hybrid interactions. Among them, the transcription factor Nuclear Factor-Y subunit C (MdNF-YC2) functions as a promoter of flowering in Arabidopsis by activating LEAFY (LFY) and APETALA1 (AP1) expression. MdFT1 showed a similar interaction pattern as MdTFL1, implying a possible antagonistic action in the regulation of flowering. These newly identified TFL1-interacting proteins (TIPs) not only expand the floral regulatory network, but may also introduce new roles for TFL1 in plant development.

Threshold‐based characteristics of apricot frost exposure at young fruit in the warm temperate zone, China

AbstractLate spring frost stress is one of the major environmental limiting factors for apricot in the warm zone in China. Investigation of frost exposure of apricot is of particular interest for estimating the frost risk, thus representing the potential damage for apricot production. In this study, daily minimum temperature (Tmin), disaster and phenological data of apricot from 1981 to 2020 in the warm zone were integrated to explore the temperature threshold on apricot at young fruit, facilitating the assessment of apricot frost exposure (E) under the background of climate warming. The daily Tmin was firstly extracted according to the historical disaster records, to identify the per‐ and ongoing weather conditions of the low‐temperature events. The overall accuracy and Receiver Operating Characteristics curve (ROC) were combined to identify the trigger threshold of apricot frost. 1.9°C was identified as the apricot frost trigger threshold in regional assessment, with relatively higher correct rate for disaster (90.2%) and lower incorrect rate for none‐disaster (23.4%). An area under the ROC curve (AUC) of 0.88 was obtained, demonstrating a good performance of Tmin as the trigger factor in discriminating between apricot frost and no frost. High frequency of days suffered from apricot and frost exposure at young fruit were mainly found in the northwestern and middle parts of the region, with frequencies of more than 2 days and E more than 3. Regional days suffered from apricot frost and E were found to have a negative trend with slope −0.0317 and −0.789, respectively, whereas the northwest and middle part of the study region were found to have an increasing trend. The results can provide technical and theoretical support for targeted apricot frost detection and risk assessment, and measures for apricot frost prevention and mitigation can be implemented according to the threshold‐based results.