Fruit Pericarp Research Articles

Management and population dynamics of Garella musculana (Erschov) (Lepidoptera: Nolidae) in newly areas, Turkey

The Walnut moth Garella (Erschoviella) musculana (Erschov) (Lepidoptera: Nolidae) seriously damages fresh shoots and fruits since first detected in 2016. The population dynamics of a newly invaded pest is important in developing management strategies in walnut areas. The populations of immature life stages, damage, overwintering, and management of G. musculana were evaluated for two consecutive years (2017-2018) in walnut orchards in Bartın, Turkey. The larvae of G. musculana were determined to damage in young shoots and under fruit pericarp. The first larva stage was recorded to feed at about 5 cm shoots of walnut trees in late-June. The adult flights were also seen in the last decade of June. Although the highest adult population was detected in July and August, significant damage was recorded in the last August and an increase occurred in September. The overwintering pupae were determined under the bark or in cardboard in early October. The damage of the collected fruits was reported about 11-60% in early harvest. The moths were caught only from melas trap throughout the cropping season in the second year, but this study was conducted on long-term population dynamics in both orchards.

Comparative transcriptomic analysis reveals the potential mechanism of hot water treatment alleviated-chilling injury in banana fruit

Banana fruit is prone to chilling injury (CI) during cold storage, resulting in quality deterioration and commodity reduction. The hot water treatment (HWT), dipping banana fruit in hot water (52 °C) for 3 min, reduced CI symptom at 7 °C storage. The purpose of this study was to investigate the potential molecular mechanism of HWT on the alleviation of CI of postharvest banana fruit. It was found that HWT treatment obviously inhibited the increases in CI index, relative electrolytic leakage, and the contents of malonaldehyde (MDA) and O2•-, while enhanced proline accumulation. Further transcriptome analysis in the pericarp of banana fruit was evaluated during storage. The results showed that differentially expressed genes (DEGs) in the comparison between control and HWT group were mainly enriched in photosynthesis, chlorophyll metabolism, lipid metabolism, glutathione metabolism, and brassinosteroid and carotenoid biosynthesis. Moreover, transcriptome expression profiles and RT-qPCR analyses exhibited that the corresponding genes involved in these metabolism pathways and heat shock proteins (HSPs) were upregulated by HWT during cold storage. In general, our findings clearly reveal the potential pathways by which HWT alleviates CI in banana fruit, enriching the theoretical basis for the application of hot water to reduce CI in fruits.

Compositional Analysis of Four Kinds of Citrus Fruits with an NMR-Based Method for Understanding Nutritional Value and Rational Utilization: From Pericarp to Juice.

Citrus is one of the most important economic crops and is widely distributed across the monsoon region. Citrus fruits are deeply loved by consumers because of their special color, fragrance and high nutritional value. However, their health benefits have not been fully understood, especially the pericarps of citrus fruits which have barely been utilized due to their unknown chemical composition. In the present study, the pericarp and juices of four typical varieties of citrus fruits (lemon, dekopon, sweet orange and pomelo) were analyzed by NMR spectroscopy combined with pattern recognition. A total of 62 components from the citrus juices and 87 components from the citrus pericarps were identified and quantified, respectively. The different varieties of the citrus fruits could be distinguished from the others, and the chemical markers in each citrus juice and pericarp were identified by a combination of univariate and multivariate statistical analyses. The nutritional analysis of citrus juices offers favorable diet recommendations for human consumption and data guidance for their potential medical use, and the nutritional analysis of citrus pericarps provides a data reference for the subsequent comprehensive utilization of citrus fruits. Our results not only provide an important reference for the potential nutritional and medical values of citrus fruits but also provide a feasible platform for the traceability analysis, adulteration identification and chemical composition analysis of other fruits.

SeedborneCercospora beticolaCan Initiate Cercospora Leaf Spot from Sugar Beet (Beta vulgaris) Fruit Tissue

Cercospora leaf spot (CLS) is a globally important disease of sugar beet (Beta vulgaris) caused by the fungus Cercospora beticola. Long-distance movement of C. beticola has been indirectly evidenced in recent population genetic studies, suggesting potential dispersal via seed. Commercial sugar beet "seed" consists of the reproductive fruit (true seed surrounded by maternal pericarp tissue) coated in artificial pellet material. In this study, we confirmed the presence of viable C. beticola in sugar beet fruit for 10 of 37 tested seed lots. All isolates harbored the G143A mutation associated with quinone outside inhibitor resistance, and 32 of 38 isolates had reduced demethylation inhibitor sensitivity (EC50 > 1 µg/ml). Planting of commercial sugar beet seed demonstrated the ability of seedborne inoculum to initiate CLS in sugar beet. C. beticola DNA was detected in DNA isolated from xylem sap, suggesting the vascular system is used to systemically colonize the host. We established nuclear ribosomal internal transcribed spacer region amplicon sequencing using the MinION platform to detect fungi in sugar beet fruit. Fungal sequences from 19 different genera were identified from 11 different sugar beet seed lots, but Fusarium, Alternaria, and Cercospora were consistently the three most dominant taxa, comprising an average of 93% relative read abundance over 11 seed lots. We also present evidence that C. beticola resides in the pericarp of sugar beet fruit rather than the true seed. The presence of seedborne inoculum should be considered when implementing integrated disease management strategies for CLS of sugar beet in the future.

Residue Analysis and the Effect of Preharvest Forchlorfenuron (CPPU) Application on On-Tree Quality Maintenance of Ripe Fruit in "Feizixiao" Litchi (Litchi chinensis Sonn.).

Litchi is a highly perishable fruit. Ripe litchi fruit loses quality quickly as they hang on tree, giving a very short hanging life and thus harvest period. This study attempted to explore the roles of cytokinin in regulating fruit ripening and senescence of litchi and examine the possibility of applying cytokinin in “on-tree storage” of the fruit. Exogenous cytokinin, forchlorfenuron (CPPU), was applied at 20 mg L−1 7 weeks after full bloom on litchi (Litchi chinensis cv. Feizixiao) fruit clusters. Color parameters, chlorophylls, anthocyanins, fruit and fruit part weights, total soluble solutes (TSSs), soluble sugars, organic acids, non-anthocyanin flavonoids, ethanol, and also CPPU residue in fruit were traced. CPPU residue was higher but decreased faster in the pericarp than in the aril, where it maintained < 10 μg kg−1. CPPU had no significant effect on fruit weight but tended to increase pericarp weight. The treatment suppressed chlorophyll loss and anthocyanin accumulation in the pericarp, increased non-anthocyanin flavonoids in the aril, but had no significant effects on non-anthocyanin flavonoids in the pericarp and total sugar and organic acids in the aril. As the commercially ripe fruit hanged on tree, TSSs, total sugar, and sucrose decreased with ethanol and acetic acid accumulation in the aril. CPPU significantly suppressed the loss of sucrose and total sugar and the accumulation of ethanol and acetic acid in the aril and inhibited malondialdehyde accumulation in the pericarp of the overripe fruit. Soluble invertase, alcohol dehydrogenase, and pyruvate decarboxylase (PDC) activity and gene expression in the aril were downregulated by CPPU. The results suggest that cytokinin partially suppresses the ripening process in litchi and is effective to slow quality loss in the overripe fruit on tree.

Examining the Inheritance of Watermelon Fruit Traits by Hayman's Graphical Approach.

Watermelon traits such as yield and other agronomic traits are highly environmentally sensitive and regulated by multiple genes; therefore, by understanding the genetic structure, the heritability and genetic influence of different traits can improve them. Five watermelon lines were crossed in a 5 × 5 full diallel parental design to estimate the genetic effect and heritability of fruit traits. Treatments were evaluated on the farm using a random complete block design. Analysis of the results showed a significant difference between genotypes, which was observed for all the studied traits at the probability level of 1%. Hayman's graphical method showed that the contribution of the nonadditive effects was more important than that of the additive effect to control most of the traits. Fruit maturation and pericarp thickness traits were regulated by incomplete dominance gene effects, and other traits were regulated by overdominance effects. The trait heritability varied between at least 0.013 and 0.352 for the fruit weight and fruit number, respectively. Results demonstrated that some traits can be modified based on the heterozygosity and production of hybrid variety methods, while the hybrid and selection in an advanced generation method can be suggested in watermelon breeding programs to breed other traits.

Modulation of NF-κB and MAPK signalling pathways by hydrolysable tannin fraction from Terminalia chebula fruits contributes to its anti-inflammatory action in RAW 264.7 cells.

Hydrolysable tannin fraction (HTF) derived from Terminalia chebula fruit pericarps was assessed for its anti-inflammatory potential in LPS-induced RAW 264.7 cells. Its molecular mechanism was also established and compared with individual tannins - chebulagic acid (CH) and corilagin (CO). The effect of HTF on LPS-stimulated RAW 264.7 cells was studied by estimating the release of NO, ROS, cytokines and changes in nuclear morphology by DAPI staining. Furthermore, the effect of HTF, CO and CH was compared with the expression of p65, p38 and pERK proteins by immunoblotting and the mRNA transcript level of COX-2, iNOS and TNF-α by quantitative PCR. The in-silico interactions of various hydrolysable tannins present in HTF with molecular targets of inflammation were studied using Maestro software. HTF at the dose levels of 25, 50 and 100 µg/ml was able to decrease the release of NO, ROS and cytokines from LPS-induced RAW 264.7 cells without disturbing the cell nuclear morphology. Investigation of molecular mechanism revealed that inhibition of NF-κB and MAPK signalling pathways was responsible for its anti-inflammatory action. The effect of HTF was higher than the individual tannins CH and CO. HTF can be developed as an effective anti-inflammatory agent.

Comparative estimations of betalains and sugars in fruits of five species of Selenicereus (Cactaceae)

Background and Aims: Betalains are water pigments reported for most species in the order Caryophyllales, to which the family Cactaceae belongs, with benefits as antioxidants in nutrition and human health. The objective of this paper is to determine the quantity of the betalains (betaxanthins and betacyanins) and sugars present in five taxa of Selenicereus, from the Hylocereus clade, commonly utilized for their edible fruit, including S. ocamponis which is an underutilized species, and scarcely cultivated in Mexico. Methods: Fruits from wild and cultivated plants were collected in Puebla, Veracruz and Yucatán (Mexico) and Valle del Cauca (Colombia) between April and June 2019, and their betalain and sugar content were estimated from frozen fruit. The method proposed by the Association of Official Analytical Chemists was followed to estimate the sugar content. A spectrophotometric method was utilized for estimation of betalains. Key results: The highest total betalain content was found in species with fruits of purple pulp and pericarp such as S. ocamponis (5.30 and 4.03 mg/100 g of fresh weight, respectively). Glucose and fructose content was considerable in some samples: S. undatus with 5.99 and 2.87 mg/100 g and S. ocamponis with 5.30 and 4.03 mg/100 g respectively. Conclusions: This study identified large variation in total betalain content in the pericarps of wild and cultivated fruits in S. undatus (2.47-37.11 mg/100 g of fresh weight), which might be related to their management and selection. Estimated total betalain content of wild plants of this species was higher than in some cultivated plants. These results suggest that wild S. undatus plants might represent a good source for breeding programs. The cultivation of species with purple pulp and pericarp should be promoted, so they can be utilized as colorants in food industry.

Regulation of tomato fruit elongation by transcription factor BZR1.7 through promotion of SUN gene expression.

Fruit shape is an important biological trait that is also of special commercial value in tomato. The SUN gene has been known as a key regulator of tomato fruit elongation for years, but the molecular mechanisms underlying its transcriptional regulation remain little understood. Here, a unique BZR1-like transcription factor, BZR1.7, was identified as a trans-acting factor of the SUN gene promoter that bound to the conserved E-box of the promoter to promote SUN gene expression. Overexpression of BZR1.7 in tomato led to elevated SUN gene expression and formation of elongated fruits. Plants of the BZR1.7 knockout mutant created by gene editing did not exhibit an observable fruit shape phenotype, suggesting possible functional redundancy of BZR1-like genes in tomato. There were seven BZR1-like genes in the tomato genome and overexpression of BZR1.5 and BZR1.6 led to elongated fruit phenotypes similar to those observed in the BZR1.7 overexpression lines, further supporting the notion of functional redundancy of BZR1-like genes in tomato fruit shape specification. Microscopic analysis revealed that there was a decreased number of cell layers in the fruit pericarp in the BZR1.7 overexpression lines. These findings offer new insights into the regulatory mechanism by which BZR1.7 promotes SUN gene expression and regulates fruit elongation in tomato.

Pepper Fruit Elongation Is Controlled by Capsicum annuum Ovate Family Protein 20.

Fruit shape is one of the most important quality traits of pepper (Capsicum spp.) and is used as a major attribute for the classification of fruit types. Wide natural variation in fruit shape exists among the major cultivated species Capsicum annuum, allowing the identification of several QTLs controlling the trait. However, to date, no genes underlying fruit shape QTLs have been conclusively identified, nor has their function been verified in pepper. We constructed a mapping population from a cross of round- and elongated-fruited C. annuum parents and identified a single major QTL on chromosome 10, termed fs10, explaining 68 and 70% of the phenotypic variation for fruit shape index and for distal fruit end angle, respectively. The QTL was mapped in several generations and was localized to a 5 Mbp region containing the ortholog of SlOFP20 that suppresses fruit elongation in tomato. Virus-induced gene silencing of the pepper ortholog CaOFP20 resulted in increased fruit elongation on two independent backgrounds. Furthermore, CaOFP20 exhibited differential expression in fs10 near-isogenic lines, as well as in an association panel of elongated- and round-fruited accessions. A 42-bp deletion in the upstream region of CaOFP20 was most strongly associated with fruit shape variation within the locus. Histological observations in ovaries and fruit pericarps indicated that fs10 exerts its effect on fruit elongation by controlling cell expansion and replication. Our results indicate that CaOFP20 functions as a suppressor of fruit elongation in C. annuum and is the most likely candidate gene underlying fs10.

O POTENCIAL DA XANTONA NATURAL α-MANGOSTINA NO DESENVOLVIMENTO DE NOVOS AGENTES ANTI-INFECCIOSOS: UMA REVISÃO

THE POTENTIAL OF NATURAL XANTHONE α-MANGOSTIN IN THE DEVELOPMENT OF NOVEL ANTIINFECTIVE AGENTS: A REVIEW. The mangosteen (Garcinia mangostana, Linn.) is a tropical fruit cultivated in the tropical forests of Southeast Asian countries. It is recognized as the queen of fruits due to its unique color, aroma, and flavor. It has been used for centuries in Southeastern Asian traditional medicine for the treatment of various diseases. Many functional molecules with high medicinal value are obtained from the pericarp of mangosteen fruit, whose major constituent is xanthone α-mangostin. Several studies have been carried out over the last decades to further investigate and understand the pharmacological properties associated with the plant and its main chemical constituents, belonging to the class of xanthones. In addition, numerous in vitro and in vivo studies related to mangosteen have been published, indicating its importance and its potential application in medicinal chemistry. Prenylated xanthones, which include α-mangostin, are secondary metabolites particularly common in plants belonging to the Clusiaceae family. These substances have been intensively investigated for their potential as biologically active agents. This article describes a critical analysis of published data related to the properties of α-mangostin, aiming to provide a more detailed view of its potential as a chemotherapeutic agent for the prevention and treatment of infectious diseases.

Assessment of combining ability in tomato genotypes (Solanum lycopersicum L.) for quality traits

Combining ability effects (GCA and SCA) were estimated using seventeen parents including fourteen females and three males of tomato (Solanum lycopersicum L.) and their hybrids developed through line × tester method. The results indicated that the lines, HUB46 for fruit firmness and number of locules, HUB36 for fruit pH (-ve direction) and shelf life, HUB3 for equatorial diameter and TSS, HUB45 for pericarp thickness and polar diameter whereas, among testers Arka Vikas for fruit firmness, pericarp thickness, fruit pH (+ve direction), polar diameter exhibited significant gca effects and considered as good general combiners. Cross combinations HUB3×DMT-2 for fruit firmness and pericarp thickness, HUB10×DMT-2 for number of locules, HUB47× Arka Vikas for fruit pH (+ve direction), HUB14× Arka Vikas for TSS, shelf life and polar diameter, HUB4×PKM-1 for equatorial diameter exhibited significant positive sca effects and regarded as good specific combiners.

Development and evaluation of hybrids resistant to late blight and leaf curl virus diseases in tomato

The current study in tomato (Solanum lycopersicum L.) was conducted at PAU, Ludhiana with the objective of developing hybrids possessing combined resistance to late blight and leaf curl virus diseases along with desirable horticultural characteristics. The experimental material which included 32 F1 hybrids (developed by line ? tester method), 12 parental lines (8 lines and 4 testers; including susceptible check Punjab Chhuhara) and standard check NS-524 were all planted in randomized complete block design with three replications. The values of ?2SCA/?2GCA were more than unity for all the traits except average fruit weight and ascorbic acid content, indicating the predominance of non-additive gene effects. Cross combinations CLN-154 ? LBR-12 and CLN-154 ? LBR-21 recorded significant heterosis over better parent and check for fruit yield and other quality characteristics. Artificial and natural screening was performed for all the experimental material against late blight and leaf curl virus diseases respectively. Out of 32 hybrids, crosses namely CLN-154? LBR-12, CLN-154 ? LBR-21, PVB-1 ? LBR-10, PVB-4 ? LBR-12 and CLN-104 ? LBR-10 were identified for combined disease resistance against late blight and leaf curl virus, in relation to desirable horticultural characteristics particularly fruit yield, average fruit weight, pericarp thickness, dry matter, titrable acidity and ascorbic acid content with fair amount of heterosis. Hence, the hybrids which displayed good potential in yield with acceptable performance of qualitative traits, along with combined disease resistance could be utilized for commercial exploitation.

Genomic markers analysis associated with resistance to Alternaria alternata (fr.) keissler-tomato pathotype, Solanum lycopersicum L.

Alternaria alternata, the causal pathogen of early blight (EB) disease, is one of the most important diseases in tomato, and other solanaceae family. We analyzed 35 tomato genotypes for quantitative/qualitative traits and biomass growth parameters, as well as the extent and structure of genetic variation associated with EB resistance. Phenotypic comparisons displayed significant differences in leaf blade width (24.95%), stem thickness (30.28%), foliage density (18.88%), and plant size (18.89%), with significant positive correlations with EB resistance (0.18-0.75). Correlation analysis showed that mature fruit size, thickness of fruit pericarp, and leaf type were significantly and negatively correlated with EB resistance (up to -0.41). The susceptible tomato seedlings represented significant reductions in biomass parameters. According to ISSR analysis, the highest resolving power (≥0.79) and heterozygosity (≥0.24) values revealed the presence of high genetic variability among the tomato genotypes. Bayesian model-based STRUCTURE analysis assembled the genotypes into 4 (best ΔK = 4) genetic groups. Combined phenotypic and molecular markers proved to be significantly useful for genetic diversity assessment associated with EB disease resistance.

15N nitrogen labelling on tomato fruit pericarp using plants cultivated in semi-controlled green house conditions

15N nitrogen labelling on tomato fruit pericarp using plants cultivated in semi-controlled green house conditions

Combination of salicylic acid and ultrasonication for alleviating chilling injury symptoms of longkong

Abstract Objectives Chilling injury is a prominent physiological disorder in longkong fruit pericarp when stored under 13 °C for a prolonged period. This study aimed to investigate the effects of individual salicylic acid (SA) and ultrasonication (US) treatments and of the combination salicylic acid and ultrasonication (SA-US) on alleviating the chilling injury symptoms in longkong fruit pericarp when in prolonged cold storage. Materials and methods SA (1 mmol/L) and US (40 kHz, 10 min at 90% amplitude, 350 W) were used as individual and combined (SA-US) treatments to control the chilling injury in longkong pericarp. The various quality measures were checked every 2 days in longkong for up to 18 days of cold storage (13 °C, 90% relative humidity). Results The results revealed that the control fruits treated with water exhibited severe chilling injury symptoms followed in rank order by US, SA, and SA-US cases. Treatments such as US and SA alone were more effective in controlling chilling injuries than control, while only minimal significant differences were noticed between them. On the other hand, the longkong pericarp treated with the SA-US combination had significantly increased antioxidant enzyme (superoxide dismutase and catalase) activities and decreased levels of membrane lytic (phospholipase D and lipoxygenase) enzymes and browning-inducing enzymes (phenylalanine ammonia lyase and polyphenol oxidase). Consequently, in the longkong pericarp, the chilling injury index, electrolytic leakage, respiration rate, weight loss, firmness, malondialdehyde content, changes in unsaturated and saturated fatty acid contents, and reactive oxygen species were significantly controlled by this treatment. Conclusions The present study concludes that longkong fruit treatment with a combination of US and SA is an excellent alternative for controlling the chilling injury symptoms and extending the shelf-life.

Combining ability and gene action analysis of some bacterial wilt resistant intraspecific hybrids of bell pepper (Capsicum annuum var. grossum)

Genetically diverse bell pepper cultivars and their 30 F1 hybrids were developed by means of diallel mating system including reciprocals. Variance analysis illustrated considerable disparity among newly developed bacterial wilt resistant hybrid lines for all the studied traits. General Combining ability (gca) effects were more pronounced than specific combining ability effects (sca). The gca effects were high with parents DPBWRC-6-1, EC-464107, EC-464115 and DPBWRC-39 for fruit yield and yield-enhancing traits. Further, reciprocal effects influenced all parameters except fruit width, TSS and lobes per fruit. Among the additive and non-additive genetic variance, the latter had a more significant influence on the inheritance of all studied characters except for fruit width and pericarp thickness. Based on sca analysis, three cross-combinations viz., DPBWRC-29×EC-464107, DPBWRC-39× DPBWRC-1 and EC-464115 × DPBWRC-29 were found to be good specific combiners for the majority of traits and can further be utilized to isolate superior segregates or released as hybrids. Key words: Gene action, General combining ability, Non-additive effect, Reciprocal effects, Specific combining ability.

Starch accumulation in bean fruit pericarp is mediated by the differentiation of chloroplasts into amyloplasts

The sucrose supply to bean fruits remains almost constant during seed development, and the early stages of this process are characterized by a significant amount of starch and soluble sugars (glucose, fructose and sucrose) accumulated in the pericarp. Bean fruits are photosynthetically active; however, our results indicated that starch synthesis in the pericarp was largely dependent on the photosynthetic activity of the leaves. The photosynthetic activity and the amount of the Rubisco large subunit were gradually reduced in the fruit pericarp, and a large increase in the amount of the ADP-glucose pyrophosphorylase small subunit (AGPase SS) was observed. These changes suggested differentiation of chloroplasts into amyloplasts. Pericarp chloroplasts imported glucose 1-P to support starch synthesis, and their differentiation into amyloplasts allowed the surplus sucrose to be used in the synthesis of starch, which was later degraded to meet the needs of fast-growing seeds. Starch stored in the bean fruit pericarp was not degraded in response to drought stress, but it was rapidly used under severe nutrient restriction. Together, this work indicated that starch accumulation in the pericarp of bean fruits is important to adjust the needs of developing seeds to the amount of sucrose that is provided to fruits.

Metabolic shifts during fruit development in pungent and non-pungent peppers

Fruit pungency is caused by the accumulation of capsaicinoids, secondary metabolites whose relation to primary metabolism remains unclear. We have selected ten geographically diverse accessions of Capsicum chinense Jacq with different pungency levels. A detailed metabolic profile was conducted in the fruit placenta and pericarp at 20, 45, and 60 days after anthesis aiming at increasing our understanding of the metabolic changes in these tissues across fruit development and their potential connection to capsaicin metabolism. Overall, despite the variation in fruit pungency among the ten accessions, the composition and metabolite levels in both placenta and pericarp were uniformly stable across accessions. Most of the metabolite variability occurred between the fruit developmental stages rather than among the accessions. Interestingly, different metabolite adjustments in the placenta were observed among pungent and non-pungent accessions, which seem to be related to differences in the genetic background. Furthermore, we observed high coordination between metabolites and capsaicin production in C. chinense fruits, suggesting that pungency in placenta is adjusted with primary metabolism.

An Improved Method for the Extraction of Nucleic Acids from Plant Tissue without Grinding to Detect Plant Viruses and Viroids.

Gene amplification techniques such as polymerase chain reaction (PCR) are widely used for the diagnosis of plant diseases caused by viruses and viroids. It is preferable that sample preparation methods for PCR or reverse transcription (RT) PCR are rapid, straightforward, and inexpensive. We previously reported a method for the extraction of nucleic acids without mechanical tissue grinding using a buffer containing potassium ethyl xanthogenate (PEX) to detect viroid RNAs. In the present report, the previous PEX method was improved and simplified. In the simplified PEX (SPEX) method, the process of PEX buffer treatment for plant cell wall disruption is improved to one step of incubation at 80 °C for 10 min, instead of three steps that took more than 26 min at 65 °C in the previous method. Total nucleic acids could be extracted from fresh, frozen, or dried leaves of a cultivar or wild species of tobacco, tomato, citron, hop plants, and pericarps of persimmon fruits by the SPEX method. Several RNA viruses and viroids were successfully detected from the extracted nucleic acids together with an internal mRNA by RT-PCR. The SPEX method may be useful for detecting not only viruses and viroids, but also other plant pathogens.