Pungency Of Capsicum Research Articles

Candidate Markers Assay for Capsicum Pungency

Effectiveness of candidate markers for differentiating the pungent, slightly pungent and non-pungent chilli lines and their use in marker assisted selection programmes was assessed. Two pungent C. annuum, one pungent C. chinense, two pungent C. frutescens, one non-pungent C. annuum, two non-pungent C. annuum var. grossum and two slightly pungent C. annuum var. acuminatum cultivars were analysed using MAP1 marker for locus Pun1, CS and B markers for locus CS, Pun11 marker for locus Pun1 of C. annuum and Pun13 marker for locus Pun1 of C. frutescens. This paper discusses the universal suitability of these candidate markers in MAS programmes for levels of pungency in Capsicum. Through sequencing of markers it is further shown that the proposed CS gene lies within the Pun1 locus and since Pun1 markers are missing in non-pungent and slightly pungent lines, we propose that genes other than Pun1 are involved in pungency mechanism in Capsicum spp.

Candidate markers assay for Capsicum pungency

Effectiveness of candidate markers for differentiating the pungent, slightly pungent and non-pungent chilli lines and their use in marker assisted selection programmes was assessed. Two pungent C. annuum, one pungent C. chinense, two pungent C. frutescens, one non-pungent C. annuum, two non-pungent C. annuum var. grossum and two slightly pungent C. annuum var. acuminatum cultivars were analysed using MAP1 marker for locus Pun1, CS and B markers for locus CS, Pun11 marker for locus Pun1 of C. annuum and Pun13 marker for locus Pun1 of C. frutescens. This paper discusses the universal suitability of these candidate markers in MAS programmes for levels of pungency in Capsicum. Through sequencing of markers it is further shown that the proposed CS gene lies within the Pun1 locus and since Pun1 markers are missing in non-pungent and slightly pungent lines, we propose that genes other than Pun1 are involved in pungency mechanism in Capsicum spp.

Mutation in the putative ketoacyl-ACP reductase CaKR1 induces loss of pungency in Capsicum.

A putative ketoacyl-ACP reductase (CaKR1) that was not previously known to be associated with pungency of Capsicum was identified from map-based cloning and functional characterization. The pungency of chili pepper fruits is due to the presence of capsaicinoids, which are synthesized through the convergence of the phenylpropanoid and branched-chain fatty acid pathways. The extensive, global use of pungent and non-pungent peppers underlines the importance of understanding the genetic mechanism underlying capsaicinoid biosynthesis for breeding pepper cultivars. Although Capsicum is one of the earliest domesticated plant genera, the only reported genetic causes of its loss of pungency are mutations in acyltransferase (Pun1) and putative aminotransferase (pAMT). In this study, a single recessive gene responsible for the non-pungency of pepper No.3341 (C. chinense) was identified on chromosome 10 using an F2 population derived from a cross between Habanero and No.3341. Five candidate genes were identified in the target region, within a distance of 220kb. A candidate gene, a putative ketoacyl-ACP reductase (CaKR1), of No.3341 had an insertion of a 4.5-kb transposable element (TE) sequence in the first intron, resulting in the production of a truncated transcript missing the region coding the catalytic domain. Virus-induced gene silencing of CaKR1 in pungent peppers resulted in the decreased accumulation of capsaicinoids, a phenotype consistent with No.3341. Moreover, GC-MS analysis of 8-methyl-6-nonenoic acid, which is predicted to be synthesized during the elongation cycle of branched-chain fatty acid biosynthesis, revealed that its deficiency in No.3341. Genetic, genomic, transcriptional, silencing, and biochemical precursor analyses performed in combination provide a solid ground for the conclusion that CaKR1 is involved in capsaicinoid biosynthesis and that its disruption results in a loss of pungency.

Isolation 3’-end Fragment of Pun1 gene from Capsicum frutescens L. cultivar Cakra Hijau

<p><em>Pun1 </em>gene <a href="file:///C:/Users/Mohamad%20Mostafa/Desktop/Knowledge%20E/In%20Press%20Conferences/ICBS-2015/Source%20files/ICBS-2015/Soure%20papers-ICBS-2015/25.%20Ria%20Reinnata-080117_Roy.doc#_msocom_1">[A1]</a> is the one of candidate gene that responsible to determine pungency in Capsicum. In previous researches, 1 310 bp fragment of 1 671 bp <em>Pun1 </em>gene from<em> Capsicum frutescens </em>L. cv. Cakra Hijau had been isolated. The purpose of this research was to isolate of 3’-<em>end</em> fragment and get full length of <em>Pun1</em> gene from <em>C. frutescens</em> L. cv. Cakra Hijau. DNA isolation was done using modified procedure. The method used to isolate the gene was PCR with a pair of primer, <em>forward primer </em>5’-GAA-GGT-GGC-AGA-AGA-ATC-AG-3’ and <em>reverse primer</em> 5’-TTG- TTG ACC-GTA-AAC-TTC-CG- 3’. The result successfully to get 715 bp length DNA fragment. The assembly of this fragment into previous research produced a full length of 1 671 bp <em>Pun1</em> gene from <em>C. frutescens</em> L. cv. Cakra Hijau consist of 738 bp first exon fragment, 348 bp intron fragment, and 585 bp second exon fragment.</p><p class="Els-Abstract-text"> </p><div><p class="Els-keywords"><strong>Keywords:</strong> C. frustescens L. cv. Cakra Hijau; gene isolation; <em>Pun1</em> gene.</p></div>

A <i>Comt</i>1 Loss of Function Mutation Is Insufficient for Loss of Pungency in <i>Capsicum</i>

The participation of O-methyltransferase (COMT) in phenylpropanoid-mediated capsaicinoid biosynthesis has long been proposed. Ferulic acid, a phenylpropanoid intermediate, is a precursor of capsaicinoid biosynthesis and is produced from caffeic acid by the action of COMT. As previously reported that silencing Comt expression caused a drastic decrease in capsaicinoid accumulation, it was presumed that a Comt loss-of-function mutation would cause loss of pungency in Capsicum. This hypothesis was tested by cloning Comt1 and Comt2 from the placenta tissue of the pungent cultivar Habanero. The phylogenetic analysis and comparison of critical amino-acid residues for enzyme function showed that the two COMTs had high similarity with the COMTs of other plant species. Moreover, as the two Comts were both expressed in placenta tissue and expressed prior to the accumulation of capsaicinoids, the two genes could be candidates for capsaicinoid biosynthesis. Second, Comt1 loss-of-function mutants were screened from the germplasm. A truncated Comt1 transcript was expressed in non-pungent pepper No.3341 caused by deletion of the genomic region. The predicted No.3341 COMT1 lacked His-265, which was absolutely necessary for enzymatic activity. Contrary to our expectations, the Comt1 mutation was not related to non-pungency of No.3341, as the deletion of Comt1 did not co-segregate with non-pungency in the F2 population obtained from crossing No.3341 with Habanero. This result was confirmed by screening several pungent accessions harboring the same Comt1 deletion mutation. Although the participation of COMT in phenylpropanoid-mediated capsaicinoid biosynthesis has long been proposed, our present study shows that Comt1 can not be a target for controlling fruit pungency.

A versatile PCR marker for pungency in Capsicum spp.

Pungency in Capsicum spp. is an important quality trait for pepper breeding. The perception of pungency in pepper is due to the presence of a group of compounds named capsaicinoids, only found within the Capsicum genus. How pungency is controlled at genetic and molecular levels has not been completely elucidated. The use of molecular markers to assess pungency trait is required for molecular breeding, despite the difficulty of development of universal markers for this trait. In this work, a DNA sequence possibly related to pungency with a high similarity to Pun1 locus was studied, and sequence analysis of this homolog revealed a 15 bp deletion in non-pungent pepper accessions. An allele-specific pair of primers was designed and specific fragments of 479 bp from non-pungent and 494 bp from pungent accessions were obtained. Polymorphism of this marker, named MAP1, was tested in a wide range of accessions, belonging to several Capsicum species, including pungent and non-pungent accessions of C. annuum L., and pungent accessions of C. chinense, C. baccatum, C. frutescens, C. pubescens, C. galapagoense, C. eximium, C. tovarii, C. cardenasii, and C. chacoense. All these Capsicum accessions were correctly discriminated. The marker suitability to assess pungency in domesticated and wild Capsicum species was demonstrated, and therefore it will be very useful in marker assisted selection (MAS). Moreover, MAP1 was located in a saturated pepper linkage map and its possible relationship with the Pun1 locus has been discussed. Among the available markers for this complex quality trait, the marker developed in this study is the most universal so far.

A Gene Encoding a Putative Acyl-transferase Involved in Pungency of Capsicum

Pungency in the fruit of pepper (Capsicum spp.) is due to the accumulation of capsaicinoids. We isolated two genes characterized as putative Capsicum acyl-transferase genes (Catf-1 and Catf-2) from the placenta of pungent pepper, which displayed consensus motifs of acyl-transferase, H***D and DFG*G. The expression pattern of Catf-1 coincided with the accumulation of capsaicinoids in pungent pepper. The Catf-1 was expressed in placenta of pungent pepper fruit, but not in other organs, such as leaf, flower, seed and pericarp. Accumulation of mRNA of Catf-1 varied with the developmental stages of the pungent pepper fruits. Genomic PCR and Southern blot studies revealed the presence of a sequence deletion at the 5′ end of the Catf-1 coding region in the non-pungent line. In the F2 population obtained from a cross between a non-pungent strain (‘mGTY-1’) and a pungent strain (‘277 long’), the genotype at the Catf-1 locus cosegregated with the phenotype for fruit pungency. These results suggest that Catf-1 is a candidate gene differentiating pungent from non-pungent peppers.

Physiological and Genetical Studies on the Pungency of <i>Capsicum</i>, V

1. トウガラシ辛味の遺伝について, 定量的研究をおこなった。辛味成分 capsaicin の定量は閾値法による簡便法を考案し, これによった (Table 1)。2. 甘親として C. annuum の大獅子 (P1, capsaicin 含有率0.05%) と伏見甘長 (P2, 0.05%), 辛親として八房 (P3, 0.25%), 鷹の爪 (P4, 0.30%) および C. frutescens Ac 1443 (P5, 1.00%) を用いた。3. 甘(♀)×辛(♂)の交雑でえた果実の測定から, メタキセニア現象は認められなかった(Table 2)。4. 甘×辛のばあい, 正逆交雑で差は認められない。F1 は辛親と同じ程度の辛さ, F2 および BF1 では甘親程度から辛親よりさらに辛いものまで分離し, その度数分布は二頂曲線となる (Tables 3, 4 および Figs. 2, 3, 5)。5. 辛×辛のばあい, F1 はより辛い親と同じ程度の辛さ, F2, BF1 および BF2 は巾の広い連続変異を示す (Table 5 および Fig 6)。6. 以上の結果, トウガラシの辛味に関して単純な分離は認められず, さらに多数の個体を用いて実験をおこなう必要がある。

Physiological and genetical studies on the pungency of Capsicum, IV. Secretory organs, receptacles and distribution of capsaicin in the Capsicum fruit_

1. Histological and histochemical observationson capsaicin-secreting organs and receptacles, and measurements of capsaicin content in variou.s parts of the fruits were carried out with four strains of Capsiculee annuum L 2. Ripe fruits of Takanotsume×Large Bell F1 were used as material for histological examination, because they contain a considerable quantity of capsaicin (O.28% of dry matter) and are large (Fig. 1). It was found that the receptacles are spherical or spheroid structures, about 0.3-1.0mm in diameter, with a thin cuticle layer on the surface 10cated along the interlocular septa. Their taste is rextremely pungent and it was confirmed by color lreaction with MARQUIS' reagent that they contained capsaicin. 3. The secretory organs consist of epidermal cells, which are slender, filled with cytoplasm and cell contents, and located just under the receptacles (Fig. 2). The development of a receptacle begins by splitting or separating of the cuticle layer from the secretory cells of a young fruit 10 days after flowering (Fig. 2) . 4. Ripe fruits of Takanotsume × Large Bell F1 Fushimi-amanaga, and Ojishi were divided into three parts : pericap, seeds, and placenta with interlocular septa, or top, middle and base of the fruit. Capsaicin content of each part was measured (Tabs. 1-3 and Fig. 3). Placenta and interlocular septa showed much more capsaicin than the other parts of the fruit. It is considered that capsaicin in pericarp and seeds is due to the adherence of the rest of the receptacles after their destruction. 5. Capsaicin content in parthenocarpic fruits of autotetraploid Takanotsume was examined. It was almost the same as that of normal fruits without seeds (Tab. 4) .