Inheritance Analysis and Identification of SSR Markers Linked to Late Blight Resistant Gene in Tomato

Late blight caused by Phytophthora infestans is the most serious disease of tomato production in China. Studies on the genetics of resistance and identification of molecular markers are very useful for breeding late blight resistant varieties. The objective of this paper was to study the inheritance of late blight resistance and identify simple sequence repeat （SSR） markers associated with resistance allele in tomato （Lycopersicon esculentum Mill）. The results came from an F2 progeny of 241 plants derived from a cross between 5~ inbred line that is susceptible to late blight and a resistant accession CLN2037E. The late blight responses of F2 plants were tested by artificially inoculation of detached-leaflets in plate and natural infection assayed under greenhouse conditions. Both methods showed that the resistance is dominant and inherited as monogenic trait. Genetic mapping and linkage analysis showed that the late blight resistance gene Ph-ROL was located on chromosome 9 with a genetic distance of 5.7 cM to the SSR marker TOM236.

Comparative Transcriptome Analysis between Cytoplasmic Male-sterile Line and Its Maintainer During the Floral Bud Development of Pepper

The male-sterile line has been largely used in the hybrid seed production of pepper, which can effectively improve the efficiency of hybrid seed production. However, the formation mechanism of male sterility in pepper remains unclear. In the present study, we compared the gene expression patterns between pepper cytoplasmic male sterile line 9704 A and its maintainer 9704 B during floral bud development using RNA sequencing technology. A total of 547 976 and 2 416 Differentially Expressed Genes(DEGs) were identified in the stage S1, S2 and S3, respectively,and more than 70% of the DEGs were down-regulated in the sterile line. Gene Ontology(GO), and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analyses were performed to further understand the functions of these identified DEGs. The results showed that the DEGs were mainly enriched in pathways of starch and sucrose metabolism, pentose and glucuronate interconversions. A number of genes, such as MS1, PME5, ATPB, and lots of transcription factors were found down-regulated in the sterile line, and we also identified a series of genes with large differences in expression patterns between sterile line and maintainer line. Collectively, our findings laid a foundation for further molecular breeding in pepper and provided new insights into its mechanism underlying the male sterility.

Novel structural annotation and functional expression analysis of GTP_EFTU conserved genes in pepper based on the PacBio sequencing data

Genes containing GTP_EFTU domain mainly express elongation factors(EF),Small GTPases,and GTP-binding proteins,which are closely related to protein synthesis,extension and ATP synthesis.In this study,we identified 39 genes containing GTP_EFTU domains from peppers.The evolutionary trees constructed from capsicum,Arabidopsis,rice,and tomato are mainly divided into 7 subfamilies.Using PacBio(Pacific Biosciences)sequencing and assembly data,we extracted these 39 gene sequences,fromwhich 25 genes had alternative splicing.Particularly,the Capana08g000545 had 16 alternative splicing processes.Accordingly,we performed promoter sequence analysis,subcellular location prediction,the expression analysis of different tissues and periods,and also the GO(Gene ontology)analysis of co-expressed genes.Lastly we did the qRTPCR analysis in 5 stages of pepper fruit development.These analyses revealed important structural and functional information for the identified 39 genes that contain GTP_EFTU domains,providing important references for further follow-up experiments to verify the genes function on plants or their unique roles in peppers.

Adaptive mechanisms of Ardisia crenata var.bicolor along an elevational gradient on Gaoligong Mountain,Southwest China

Plants overcome environmental stress by generating metabolic pathways.Thus,it is crucial to understand the physiological mechanisms of plant responses to changing environments.Ardisia crenata var.bicolor has an important ornamental and medicinal value.To reveal the impact of elevational gradient on the habitat soil and plant physiological attributes of this species,we collected root topsoil(0–20 cm)and subsoil(20–40 cm)samples and upper leaves at the initial blooming phase,in a survey of six elevations at 1,257 m,1,538 m,1,744 m,1,970 m,2,135 m,and 2,376 m,with 18 block plots,and 5sampling points at each site.Temperature decreases with an increase in elevation,and soil variables,and enzymatic activities fluctuated in both the topsoil and subsoil,with all of them increasing with elevation and decreasing with soil depth.Redundancy analysis was conducted to explore the correlation between the distribution of A.crenata var.bicolor along the elevational gradient and soil nutrients and enzyme activities,the soil properties were mainly affected by p H at low elevations,and governed by total phosphorus(TP)and available nitrogen(AN)at high elevations.The levels of chlorophyll,carbohydrates,and enzymatic activity except for anthocyanin in this species showed significant variation depending on physiological attributes evaluated at the different collection elevations.The decline in chlorophyll a and b may be associated with the adaptive response to avoid environmental stress,while its higher soluble sugar and protein contents play important roles in escaping adverse climatic conditions,and the increases in activities of antioxidant enzymes except peroxidase(POD)reflect this species’higher capacity for reactive oxygen scavenging(ROS)at high elevations.This study provides supporting evidence that elevation significantly affects the physiological attributes of A.crenata var.bicolor on Gaoligong Mountain,which is helpful for understanding plant adaptation strategies and the plasticity of plant physiological traits along the elevational gradients.

Research Progress on Manglietia ventii,A Wild Plant Species with Extremely Small Populations

Manglietia ventii is a wild plant species with extremely small populations endemic to Yunnan,mainly distributed in southeast Yunnan.Due to the continuous deterioration of natural habitats,excessive felling and utilization of human beings,and the decline of breeding ability,the number of individuals in the population has decreased significantly.Through field investigation and literature review,the research status of M.ventii in systematics,conservation ecology,reproductive biology,genetic diversity,endangered mechanism and resource protection at home and abroad are systematically reviewed.And the future research direction is prospected.It is necessary to strengthen the research on the basic characteristics of M.ventii,explore the transmission route of M.ventii and deepen the development and utilization of resources,in order to provide a theoretical support for the protection and sustainable utilization of germplasm resources of M.ventii,and provide a reference for the protection of other wild plant species with extremely small populations.

The antioxidant activity,c-glucosidase and acetylcholinesterase inhibition activity,and chemical composition of Paeonia delavayi petal

Objectives:This study aimed to evaluate the functional activity and phytochemical composition in the flower petals of Paeonia delavayi(P delavay)in different colors.Materials and Methods:P delavayi petal extracts were prepared by maceration in methanol,including purple petal extract(PPE),red petal extract(RPE),and yellow petal extract(YPE),and their antioxidant activity and x-glucosidase and acetylcholinesterase inhibition activities were evaluated.To correlate these measured activities to phytochemicals in the petals,an ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS)-based metabolomics method was applied to profile the compositions in the petals of different colors.Finally,the Kyoto Encyclopedia of Genes and Genomes(KEGG)metabolic pathways database was used to identify the related metabolic pathways that are responsible for the production of these polyphenolic phytochermicals in the petals.Results:The results showed that PPE had the highest total phenolic content,total flavonoid content,and the strongest 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt(ABTS)radical scavenging ability,ferric reducing antioxidant power,and acetylcholin-esterase inhibition ability in all three samples,while YPE showed the strongest 2,2-diphenyl-1-picrylhydrazyl(DPPH)scavenging activity and x-glucosidase inhibition ability.A total of 232 metabolites were detected in the metabolomic analysis,198 of which were flavonoids,chalcones,flavonols,and anthocyanins.Correlation analysis indicated that peonidin-3-O-arabinoside and cyanidin-3-O-arabinoside were the major contribu-tors to the antioxidant activity.Principal component analysis showed a clear separation among these three petals.In addition,a total of 38,98,and 96 differential metabolites were identified in PPE,RPE,and YPE,respectively.Pathway enrichment revealed 6 KEGG pathways that displayed significant enrichment differences,of which the anthocyanin biosynthesis,flavone and flavonol biosynthesis were the most enriched signaling pathways,revealing a potential reason for the differences in met abolic and functional levels among different colors of P delavayi petal.Conclusions:P.delavayi petals in different colors have different metabolite contents and functional activities,of which the anthocyanin,flavone,and flavonol metabolites are critical in its functional activities,suggesting the anthocyanin biosynthesis,flavone and flavonol biosynthesis path-ways are the key pathways responsible for both petal color and bioactive phytochemicals in P delavayi flowers.

Research progress on the MYB transcription factors in tropical fruit

Tropical fruits,such as bananas,passion fruit,mangoes,and lychees,are rich in vitamins,flavonoids and non-flavonoid phenols,and are the healthiest way to intake bioactive compounds in one's daily diet.Coupled with their unique taste,tropical fruits are becoming more increasingly popular.The production of bananas is second only after grapes,while other tropical fruit are limited by the planting environment,resulting in a relatively low planting area and yield.With the improvement in breeding technology and planting technology,the development of tropical fruit crops will have broad prospects.MYB plays a major regulatory role in several biological processes,including growth and development of plants,quality formation,and stress resistance.There is a comparatively junior level of research on tropical fruit crops compared to grain fruit and model plants.Despite the progress that has been made in the development of molecular biology methods that can transform the genetic makeup of tropical fruit crops,the functional understanding of the multiple MYB genes is still in its initial stages.This paper aims to review the current status of the research on the development of these genes and their prospects.It is expected to provide a reference for the study of MYB transcription factors in tropical fruit crops and to provide new ideas for the functional resolution of MYB transcription factors in different biological processes.

CmbHLH110,a novel bHLH transcription factor,accelerates flowering in chrysanthemum

Basic helix-loop-helix(bHLH)transcription factor gene family in plants controls various growth and development aspects;however,the actual roles of these genes in flowering plants are not well known.In this study,a novel bHLH protein CmbHLH110 was found to interact with CmERF110 by in vitro and in vivo experiments,a chrysanthemum ERF110 homolog that acts as a positive flowering regulator.In addition,CmbHLH110 was also found to regulate the flowering of chrysanthemums,overexpression of CmbHLH110 causes chrysanthemums to flower earlier,and suppressed CmbHLH110 leads to delayed flowering.Furthermore,the loss-of-function Arabidopsis mutant of its homologue PERICYCLE FACTOR TYPE-A 5(PFA5)had a noticeable late flowering phenotype,and CmbHLH110 completely complemented the late flowering phenotype of the pfa5 mutant,whereas heterologous overexpression of CmbHLH110 in Arabidopsis Col-0 caused early flowering.Transcriptome sequencing revealed significant differential expression of flowering-related and circadian clock-related genes in transgenic chrysanthemum.Therefore,we concluded that CmbHLH110,as a novel flowering regulator,could interact with CmERF110 to regulate flowering in chrysanthemum.