The Clausena lansium genome provides new insights into alkaloid diversity and the evolution of the methyltransferase family

Wampee(Clausena lansium)is an important evergreen fruit tree native to southern China that has a long history of use for medicinal purposes.Here,a chromosome-level genome of C.lansium was constructed with a genome size of 282.9 Mb and scaffold N50 of 30.75 Mb.The assembled genome contains 48.70%repetitive elements and 24,381 protein-coding genes.Comparative genomic analysis showed that C.lansium diverged from Aurantioideae 15.91-24.95 million years ago.Additionally,some expansive and specific gene families related to methyltransferase activity and S-adenosylmethionine-dependent methyltransferase activity were also identified.Further analysis indicated that N-methyltransferase(NMT)is mainly involved in alkaloid biosynthesis and O-methyltransferase(OMT)participates in the regulation of coumarin accumulation in wampee.This suggested that wampee's richness in alkaloids and coumarins might be due to the gene expansions of NMT and OMT.The tandem repeat event was one of the major reasons for the NMT expansion.Hence,the reference genome of C.lansium will facilitate the identification of some useful medicinal compounds from wampee resources and reveal their biosynthetic pathways.

MaDREB1F confers cold and drought stress resistance through common regulation of hormone synthesis and protectant metabolite contents in banana

Adverse environmental factors severely affect crop productivity.Improving crop resistance to multiple stressors is an important breeding goal.Although CBFs/DREB1s extensively participate in plant resistance to abiotic stress,the common mechanism underlying CBFs/DREB1s that mediate resistance to multiple stressors remains unclear.Here,we show the common mechanism for MaDREB1F conferring cold and drought stress resistance in banana.MaDREB1F encodes a dehydration-responsive element binding protein(DREB)transcription factor with nuclear localization and transcriptional activity.MaDREB1F expression is significantly induced after cold,osmotic,and salt treatments.MaDREB1F overexpression increases banana resistance to cold and drought stress by common modulation of the protectant metabolite levels of soluble sugar and proline,activating the antioxidant system,and promoting jasmonate and ethylene syntheses.Transcriptomic analysis shows that MaDREB1F activates or alleviates the repression of jasmonate and ethylene biosynthetic genes under cold and drought conditions.Moreover,MaDREB1F directly activates the promoter activities of MaAOC4 and MaACO_(2)0 for jasmonate and ethylene syntheses,respectively,under cold and drought conditions.MaDREB1F also targets the MaERF11 promoter to activate MaACO_(2)0 expression for ethylene synthesis under drought stress.Together,our findings offer new insight into the common mechanism underlying CBF/DREB1-mediated cold and drought stress resistance,which has substantial implications for engineering cold-and drought-tolerant crops.

Identification of key genes involved in flavonoid and terpenoid biosynthesis and the pathway of triterpenoid biosynthesis in Passiflora edulis

Passion fruit(Passiflora edulis Sims) is a vine of the Passiflora genus in the Passifloraceae family. The extracted components include flavonoids and terpenoids, which have good anti-anxiety and anti-inflammatory effects in humans.In this study, we analyzed the transcriptomes of four tissues of the ‘Zixiang’ cultivar using RNA-Seq, which provided a dataset for functional gene mining. The de novo assembly of these reads generated 96 883 unigenes, among which 61 022 unigenes were annotated(62.99% yield). In addition to its edible value, another important application of passion fruit is its medicinal value. The flavonoids and terpenoids are mainly derivatives of luteolin, apigenin, cycloartane triterpenoid saponins and other active substances in leaf extracts. A series of candidate unigenes in the transcriptome data that are potentially involved in the flavonoid and terpenoid synthesis pathways were screened using homologybased BLAST and phylogenetic analysis. The results showed that the biosynthesis of triterpenoids in passion fruit comes from the branches of the mevalonate(MVA) and 2-C-methyl-D-erythritol 4-phosphate/1-deoxy-D-xylulose 5-phosphate(MEP/DOXP) pathways, which is different from the MVA pathway that is used in other fruit trees. Most of the candidate genes were found to be highly expressed in the leaves and/or flowers. Quantitative real-time PCR(qRT-PCR) verification was carried out and confirmed the reliability of the RNA-Seq data. Further amplification and functional analysis of these putative unigenes will provide additional insight into the biosynthesis of flavonoids and terpenoids in passion fruit.

Chromosome-scale genome assembly provides insights into the evolution and flavor synthesis of passion fruit (Passiflora edulis Sims)

Passion fruit(Passiflora edulis Sims)is an economically valuable fruit that is cultivated in tropical and subtropical regions of the world.Here,we report an~1341.7Mb chromosome-scale genome assembly of passion fruit,with 98.91%(~1327.18Mb)of the assembly assigned to nine pseudochromosomes.The genome includes 23,171 protein-coding genes,and most of the assembled sequences are repetitive sequences,with long-terminal repeats(LTRs)being the most abundant.Phylogenetic analysis revealed that passion fruit diverged after Brassicaceae and before Euphorbiaceae.Ks analysis showed that two whole-genome duplication events occurred in passion fruit at 65 MYA and 12 MYA,which may have contributed to its large genome size.An integrated analysis of genomic,transcriptomic,and metabolomic data showed that‘alpha-linolenic acid metabolism’,‘metabolic pathways’,and‘secondary metabolic pathways’were the main pathways involved in the synthesis of important volatile organic compounds(VOCs)in passion fruit,and this analysis identified some candidate genes,including GDP-fucose Transporter 1-like,Tetratricopeptide repeat protein 33,protein NETWORKED 4B isoform X1,and Golgin Subfamily A member 6-like protein 22.In addition,we identified 13 important gene families in fatty acid pathways and eight important gene families in terpene pathways.Gene family analysis showed that the ACX,ADH,ALDH,and HPL gene families,especially ACX13/14/15/20,ADH13/26/33,ALDH1/4/21,and HPL4/6,were the key genes for ester synthesis,while the TPS gene family,especially PeTPS2/3/4/24,was the key gene family for terpene synthesis.This work provides insights into genome evolution and flavor trait biology and offers valuable resources for the improved cultivation of passion fruit.

The Cause for Water-Heart Fruit of Pineapple and Protective Measurements

Pineapple industry has played important roles in China’s economics in tropical- and subtropical-areas. Pineapple industry in China has been damaged by water-heart fruit. The objective of this research is to clarify the mechanism underlying water-heart fruit of pineapple and find ways for preventing water-heart fruit. We found that water logging can cause water-heart pineapple. The longer the pineapple plants were water logged, the more fruits were found water heart. With the development of fruits, the fruits’ sensitivity to water logging increased. Spraying potassium sulfate onto the fruits after the plants are water logged can decrease the rate of pineapple water-heart. But this effect became less with the fruit development. When sucrose and its precursors in intracellular space were transferred into sink cells, hydrogen ions were required. Because of lacking hydrogen ions, sucrose and its precursors were stopped in intracellular space and seized water from cells. Water-heart fruit formed. If potassium can be gotten in intracellular space, the roles of hydrogen ions might be replaced with potassium ions. With the help of potassium ions, sucrose and its precursors were transported into sink cells and the water-heart symptoms alleviated.

The Situation and Challenges of Pineapple Industry in China

Pineapple is the third largest tropical fruit in China. Pineapple industry played important roles in developing economies in tropical- and subtropical-areas in China. However, the structure of varieties is simple. The harvesting period is centralized. The price of pineapple fruits is often low. These challenges hindered the further development of pineapple industry. The people engaged in pineapple industry should select and cultivate new varieties with higher qualities and that can be harvested in a longer period. More work should be done in the technology on inducing inflorescence of new varieties. Precision fertilization for new varieties should be researched and developed. The technology for cultivating tissue-culture seedlings fast and at low cost should also be studied. The diseases in fruits should be prevented and controlled before harvesting.

Molecular identification of the key starch branching enzyme-encoding gene SBE2.3 and its interacting transcription factors in banana fruits

Starch branching enzyme(SBE)has rarely been studied in common starchy banana fruits.For the first time,we report here the molecular characterization of seven SBE(MaSBE)and six SBE(MbSBE)genes in the banana A-and B-genomes,respectively,which could be classified into three distinct subfamilies according to genome-wide identification.Systematic transcriptomic analysis revealed that six MaSBEs and six MbSBEs were expressed in the developing banana fruits of two different genotypes,BaXi Jiao(BX,AAA)and Fen Jiao(FJ,AAB),among which MaSBE2.3 and MbSBE2.3 were highly expressed.Transient silencing of MaSBE2.3 expression in banana fruit discs led to a significant decrease in its transcription,which coincides with significant reductions in total starch and amylopectin contents compared to those of empty vector controls.The suggested functional role of MaSBE2.3 in banana fruit development was corroborated by its transient overexpression in banana fruit discs,which led to significant enhancements in total starch and amylopectin contents.A number of transcription factors,including three auxin response factors(ARF2/12/24)and two MYBs(MYB3/308),that interact with the MaSBE2.3 promoter were identified by yeast one-hybrid library assays.Among these ARFs and MYBs,MaARF2/MaMYB308 and MaARF12/MaARF24/MaMYB3 were demonstrated via a luciferase reporter system to upregulate and downregulate the expression of MaSBE2.3,respectively.

Molecular-based Integrated Identification of Bacterial Blight(Xanthomonas axonopodis pv. dieffenbachiae) in Anthurium and Detection of Latent Infection

Bacterial blight, caused by Xanthomonas axonopodis pv. dieffenbachiae （Xad）, is the most destructive disease of anthurium worldwide, and no effective control technique has been developed currently. The comprehensive survey and precise detection of the pathogen is essential for evaluating disease progress and strengthening management to avoid a serious epidemic. In this study, a total of 253 blight-suspected samples of anthurum and other Araceae species were collected across the country, and 166 potential pathogenic bacteria strains were isolated and purified, after combined analysis on the characteristics of morphology, pathoge- nicity, 16S rDNA sequences and amplicans of Xad-specific SCAR markers. Finally, 93 of which were considered as X. axonopod/s pv. dieffenbachiae. In addition, by using a nested-PCR in repeated detections, 17 out of 21 prevalent anthurium cultivars without blight symptom exhibited latent infection even in young leaves. The results indicated that the anthurium bacterial blight distributed commonly in growing areas in China, and most of the commercial cuhivars had no strong resistance. The identification of Xad infection （latent） would be beneficial for the disease forecasting and management improving in anthttrium production.

The Responses of Pineapple Varieties to Forced-Flower Treatment at Seedling Stage

Forcing flower is an important step for planting pineapple. Although many papers have been reported about forcing flower for pineapple plants on the aim of harvesting fruits, no reports have been found about forcing flower at seedling phase for preparing bonsai. In this paper, Tainong 4, Tainong 16 and Tainong 17 plants with 20 leaves were watered on stem apex with 40 ml of 0.13% of ethephron. Results showed that most of Tainong 4 plants flowered after being treated 30 days. None plant of Tainong 16 flowered after being treated 60 days. In the same variety, for example, Tainong 4, some plants flowered earlier, some plants flowered late. Tainong 4 was the most sensitive to ethephron at early-growth phase. Tainong 16 was the most insensitive variety. The low flower rate in this research might be due to that the pineapple plants were in early-vegetative-growth stage. They had not appropriate physiological conditions for forcing flowers. For making pineapple bonsai at early-vegetative-growth phase, higher doses of forcing-flower agent should be used than those of forcing-flower agent for harvesting fruits.

A Simple Method for Pineapple Seedling Propagation

Pineapple is nutrient and planted in many tropical and subtropical countries. Plenty of elite seedlings were always needed in short time. The common methods for propagating pineapple seedlings have low-multiplying index or take long time. A new method was introduced in this paper. Shoots were induced using stem sections. And then, the shoot bases were cut and cultured on callus-induced medium. The meristematic granules induced were cultured on shoot-induced medium. Shoots can be induced from the meristematic granules. Seedlings can be induced from these shoots in short time. This method overcomes the defects of the common ways. Enough seedlings can be gotten in short time. The operation is simple and easy to learn.

Identification Cold Tolerance of Pineapple Germplasms at Seedling Stage

Pineapple plant was always injured due to low temperature. Breeding varieties with high cold tolerance was the supreme way to resolve this problem and identifying cold tolerance of germplasms collected was necessary. In this study, SSR locus around homologous sequences of cold-tolerant genes was searched and screened using MD-2 (cold-tolerant variety) and Tainong 17 (cold-sensitive variety). Seventy three pairs of primers of which PCR results were different between these two varieties were gotten. PCRs were performed using these as primers and genomic DNA of germplasms collected as templates. Six pairs of primers were found that their PCR results were in good consistent with cold tolerance. Using GLM (General linear model) association mapping analysis, two SSR markers linked to cold tolerance were found. Their efficiency was verified further using pineapple germplasms with high cold tolerance which had been validated in field by cold wave. They will be used in cold-tolerant breeding of pineapple in the future.

Effect of Banana Stalk Organic Fertilizer on the Growth of Chinese Cabbage

In order to solve the problem of waste disposal after banana harvest,we use banana stalk to produce banana stalk organic fertilizer,through a plot experiment. We compare the influence of normal organic fertilizer( Wanlubao) and banana stalk organic fertilizer as base fertilizers on Chinese cabbage growth,and evaluate the economic benefits of banana stalk organic fertilizer. The results show that organic fertilizer has little effect on water content and nutrient content of Chinese cabbage,but has significant effect on plant height and leaf width. Using organic fertilizer can increase the production of Chinese cabbage by 22. 50%- 43. 10%. With 6750 kg / ha normal organic fertilizer,Chinese cabbage gets the highest yield,which reaches 30135 kg / ha,followed by the treatment of 6750 kg / ha stalk organic fertilizer. At farmers' conventional fertilization level( 4500 kg / ha),stalk organic fertilizer can increase the yield by more than 3. 50% in comparison with the normal organic fertilizer,and the economic benefit increases by 1800 yuan / ha. As a kind of banana waste cycling product,banana stalk organic fertilizer is of low cost and good effect,and can be used instead of normal organic fertilizer.

Cultivation and Management Technologies for New Banana Cultivar ‘Refen 1’(Musa Spp. ABB,Pisang Awak Subgroup)

Banana is one of the most important crops in tropical and subtropical regions of China. Fenjiao( Musa Spp. ABB,Pisang Awak subgroup) has been grown by small scale famers because of its stable market price and better sugar-acid blend. However,the traditional Fenjiao variety is susceptible to banana Fusarium wilt,has a high plant height( over 5. 0 m),and farmers lack large-scale planting techniques.Based on the traditional Fenjiao variety,we selected‘Refen 1’variety through mutagenesis technology,which has low temperature resistance,suitable to marginal soils and relatively low plant height( 3. 2-4. 0 m). This paper mainly introduces the major techniques of propagation,cultivation,and post-harvest stages of‘Refen 1’banana,including the selection of explant materials,treatment,disinfection,initial culture,nursery hardening of in vitro-produced banana plants,and transplant of tissue culture seedlings. The major points of the cultivation technology include banana plantation selection and preparation,planting methods,irrigation and fertilizer management,pruning and retaining,and prevention and control of plant diseases and insect pests.

Fatty Acid Accumulation in Seeds of Three Seed Pumpkin Cultivars

In the literature there are many reports on the composition and properties of pumpkin seed oil; however, few is known about the effect of different stages of seed development on various fatty acid profiles in developing seeds. The objective of this study was to provide the changes of various fatty acid accumulations in seed oil obtained from the seeds of three pumpkin varieties belonging to the species Cucurbita maxima and Cucurbita pepo. Unsaturated acids(oleic and linoleic) were dominant in various fatty acids, which constituted 38.9%-49.1% and 29.4%-42.7% of the total fatty acids at seed maturity for three pumpkin varieties, respectively, while other fatty acid concentrations except for palmitic acid all did not reach 10%. Different varieties exhibited greater effect on various fatty acid contents and the total fatty acid contents in the seeds of pumpkin rather than the species. On the whole, palmitic acid profiles of the seed oil in three varieties all followed the fluctuant decrease during all the stages of seed development, but palmitoleic acid and the total fatty acid profiles of the seed oil in three varieties were just the opposite. Stearic, oleic and linoleic acid profiles of the seed oil in three varieties all experienced the third pattern that fluctuated during all the stages of seed development, but no significant differences in these three fatty acid concentrations were found from the beginning to the end. Linolenic acid concentrations of three varieties were on the decline and ultimately close to zero. Myristic and arachidic acid profiles of the seed oil followed different trends in three varieties. Among them, myristic and arachidic acid profiles of the seed oil of Yinhui-1 fluctuated downward all the time until seed maturity, but those of 0238-1 and Jinhui-2 completely changed oppositely.

A Method to Improve the Embryogenesis Rate of Banana Somatic Cell Embryogenesis

Getting embryogenic callus is the first step for banana transformation. Enhancing embryonic-callus-rate is important for banana molecular breeding. In this paper, WIND1, an AP2/ERF transcription factor was added into the embryonic-callus-inducing medium with poly-Arg and nuclear localization signal (NLS). The embryogenic-callus-induced rate of the immature male florescence cultured on the media containing the recombinant protein Arg9-NLS-WIND1 was significantly higher than that of the immature male florescence cultured on the control media. Medium containing 0.01% of the protein Arg9-NLS-WIND1 had the best effect for inducing the embryogenesis of the immature male inflorescence. On the medium containing 0.01% of the protein Arg9-NLS-WIND1, 11.5% of the immature male flowers can develop embryonic callus. On the medium containing Arg9-NLS-WIND1, the protein might be transferred into cytoplasm of the explants by endocytosis due to the interaction between the poly-Arg transduction domain and the plasma membrane. After it entered the nucleus guided by NLS and bind with the target DNA domain, the somatic cell embryogenesis reactions were initiated and the embryonic callus formed.

The Effects for Delaying Banana Seedling Growth through Spraying Growing Retardants on Stem Apex

Replanting is always required for banana farmers. Selecting growth retardants is important for banana seedling companies. Stem apex contained many gibberellins. Seven treatments were performed onto stem apex of banana seedlings in this research. Results showed that heights of seedlings sprayed with paclobutrazol (200 mg/L), dniconazole (200 mg/L), and dniconazole + brassins (200 mg/L + 0.1 mg/L) were significantly lower than those of seedlings sprayed with water. Paclobutrazol was the ideal retardant for delaying the growth of leaf if stem apex was selected as a treated candidate. Fresh weights of seedlings of all seven treatments were significantly less than that of control. For delaying the growth of fresh weight of banana seedlings, chlormequat chloride (200 mg/L) was the best choice. Reducing power of roots of seedlings treated with 100 ml of paclobutrazol (200 mg/L) was significantly higher than that of seedling treated with water. Chlorophyll contents of seedlings treated with growth retardants were significantly higher than that of seedlings treated with water.

Factors Related to Physical Strength of Banana Pseudostem

Banana is an important fruit in China. Banana production played important role in economic development in tropical region. Banana production in China was always cut because of lodging caused by typhoon. Getting new cultivars with high resistance to lodging is the basic resolution to resolve this problem. Screening and identifying the germ plasm resource is the first step to breed new cultivars. Banana plant height was high. A single banana plant needs large area. It is difficult to screen the germ plasm resource by identifying the physical strength of banana pseudostem. This research focused on studying the relationship between pseudostem and plant height, pseudostem diameter, acid soluble lignin, acid insoluble lignin, total lignin, pore numbers of pseudostem cross section, and the expression of 4-coumarate:CoA ligase (4CL). Results showed that the plant with high physical strength in seedling stage always has high physical strength in mature stage. The physical strength of banana seedling pseudostem was closely related to pseudostem diameter and total lignin. Pseudostem diameter and total lignin can be used to predict the physical strength of mature banana pseudostem. Work on identifying and screening the physical strength of banana germ plasm pseudostem can be reduced by measuring seedling pseudostem diameter and total lignin in pseudostem of banana germplasm.

Accumulation of Sugars and Liquid in Apoplast of Fruit Flesh Result in Pineapple Translucency

Translucency is a recurring problem for pineapple industry. Translucent fruit contained more sucrose, glucose and fructose in apoplast than those in apoplast of normal fruit. There were more liquid in intercellular space of translucent fruit than that of normal flesh. The contents of alcohol and ethylene in translucent fruit were higher than those in normal fruit. Translucent fruit contained less calcium than normal fruit. Electrolyte leakage of translucent flesh was more than that of normal flesh. There were 205 proteins of which the expressions in translucent flesh were higher than those in normal flesh. Calcium-ions-binding protein EF-hand domain-containing protein, ethylene-synthesizing enzyme 1-aminpcyclopropane-1-carboxylate oxidase, ROS-producing protein universal stress protein A-like protein were the top three proteins of which the expressions in translucent flesh were higher than those in normal fruit. When much sugar was transferred into fruit pulp and accumulated in intercellular space, water will be absorbed from cells around and translucence formed. The accumulation of sugar and liquid in apoplast were due to that cell wall and membrane were degraded, which was from being attacked by ROS. There might be more and larger pores in cell wall and membranes of translucent flesh. These data played foundations for researching methods for controlling pineapple translucency.

A Method for Prolonging Culturing Time of Banana Seedling in Nursery Shed

Banana industry plays important roles in the economics of southern China, where is always blown by typhoon in summer and autumn. After typhoon passed through, fresh banana seedlings are often required. That is a problem for companies on culturing banana seedling, since culturing banana seedlings takes about four months and typhoon cannot be predicted so early. If the growth of banana seedlings can be slowed down and the seedlings can be cultured in nursery shed for more time, this problem will be solved. In this research, seven treatments (paclobutrazol, diniconazole, paclobutrazol + brassins, paclobutrazol + diethyl aminoethyl hexanoate, diniconazole + brassins, diniconazole + diethyl aminoethyl hexanoate, chlormequat chloride) were performed on banana seedlings and the growth was measured. Results showed that in all of the treatments, the values of plant height, leaf length, pseudostem diameters, root length, root weight, root volume, fresh weight of above-ground tissues and fresh weight of seedlings were significantly less than those corresponding values of control. The reducing powers of roots of seedlings sprayed with paclobutrazol and paclobutrazol + diethyl aminoethyl hexanoate were remarkably higher than those of seedlings treated with water. Total chlorophyll content in leaves of seedlings sprayed with paclobutrazol was remarkably higher than that of seedlings treated with water. Total chlorophyll contents in leaves of seedlings treated with paclobutrazol + diethyl aminoethyl hexanoate and chlormequat chloride were lower than those of control. For delaying the growth of banana seedlings, chlormequat chloride was the best among the seven treatments. The mechanism might be that the enzyme CPP-synthase in seedlings was inhibited by chlormequat chloride.

A Method to Predict Banana Pseudostem’s Strength at Seedling Stage

Banana industry played important roles in Chinese economics. Banana production was always affected heavily by typhoon. Selecting new cultivars with high strength was the basic way to resolve this problem. If the selecting work was performed at mature stage, it will need large area and much labor. If this work can be done at seedling stage, this process will be simplified significantly. We found that banana plants that had high strength at seedling stage always had high strength at mature stage. The physical strength of seedling pseudostem was closely related with pseudostem diameter, lignin content and the expression of 4-coumarate:CoA ligase gene Mu4CL15. Those seedlings whose pseudostem had bigger diameter, more lignin content and higher expression of Mu4CL15 always had higher strength to resist lodging. Through screening plants whose pseudostem had bigger diameter, more lignin content and higher expression of Mu4CL15, plants with high-strength pseudostem can be selected. Using this method, thousands of seedlings can be identified in short time. This process does not need large area and much labor. If this method was applied, the process of breeding new cultivars of banana with high resistance to lodging will be accelerated.