Isolation and Properties of Floral Defensins from Ornamental Tobacco and Petunia

Lay, Fung T.; Brugliera, Filippa; Anderson, Marilyn A.

doi:10.1104/pp.102.016626

Cited by 200 publications

(209 citation statements)

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“…These TPIs could inhibit gut proteinases of herbivores and might help to defend against florivores. The accumulation of defensin proteins in N. attenuata flowers is similar to the levels reported from N. alata and Petunia flowers (62). The antifungal activity of N. alata defensin has been established (63) and because insect-vectored pollination is known to increase the possibility of pathogen infection, the floral defensins of N. attenuata might function in pathogen resistance.…”

Section: Discussionsupporting

confidence: 56%

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Flower-specific jasmonate signaling regulates constitutive floral defenses in wild tobacco

Wang

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Optimal defense (OD) theory predicts that within a plant, tissues are defended in proportion to their fitness value and risk of predation. The fitness value of leaves varies greatly and leaves are protected by jasmonate (JA)-inducible defenses. Flowers are vehicles of Darwinian fitness in flowering plants and are attacked by herbivores and pathogens, but how they are defended is rarely investigated. We used Nicotiana attenuata, an ecological model plant with well-characterized herbivore interactions to characterize defense responses in flowers. Early floral stages constitutively accumulate greater amounts of two well-characterized defensive compounds, the volatile (E)-α-bergamotene and trypsin proteinase inhibitors (TPIs), which are also found in herbivore-induced leaves. Plants rendered deficient in JA biosynthesis or perception by RNA interference had significantly attenuated floral accumulations of defensive compounds known to be regulated by JA in leaves. By RNA-seq, we found a JAZ gene, NaJAZi, specifically expressed in early-stage floral tissues. Gene silencing revealed that NaJAZi functions as a flower-specific jasmonate repressor that regulates JAs, (E)-α-bergamotene, TPIs, and a defensin. Flowers silenced in NaJAZi are more resistant to tobacco budworm attack, a florivore. When the defensin was ectopically expressed in leaves, performance of Manduca sexta larvae, a folivore, decreased. NaJAZi physically interacts with a newly identified NINJA-like protein, but not the canonical NINJA. This NINJA-like recruits the corepressor TOPLESS that contributes to the suppressive function of NaJAZi on floral defenses. This study uncovers the defensive function of JA signaling in flowers, which includes components that tailor JA signaling to provide flower-specific defense

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Section: Discussionsupporting

confidence: 56%

“…Plant defensins are small, cysteine-rich proteins with antimicrobial activity. Floral defensins were first identified in Nicotiana alata and Petunia plants and are thought to have antifungal activity in vitro (62,63). The regulation of floral defensin remains unclear.…”

Section: Resultsmentioning

confidence: 99%

Flower-specific jasmonate signaling regulates constitutive floral defenses in wild tobacco

Wang

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Genes of plant defensins are expressed in different organs, e.g. seeds [7,8], leaves [9], roots [10], flowers [11,12] and symbiotic tubercles [13]. There is both constitutive and inducible expression of genes, encoding plant defensins [11,14].…”

mentioning

confidence: 99%

“…There is both constitutive and inducible expression of genes, encoding plant defensins [11,14]. The main function of defensins is to inhibit fungal disease [8,11,15], but for some peptides there are antibacterial activity [16,17], inhibition of trypsin [18], and participation in the formation of resistance to heavy metals [19], cold stress [20,21], drought [22], salinity [23,24] and in developmental processes [25].…”

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confidence: 99%

PLANT DEFENSINS: BIOLOGICAL FUNCTION, MECHANISMS OF ACTION AND METHODS OF ANALYSIS (review)

Kulaeva¹,

Kliukova²,

Повыдыш³

et al. 2017

S-h. biol.

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A b s t r a c tOne of the actual problems of modern agriculture is crop loss due to various biotic and abiotic factors. In plants there is a multicomponent protection system, including the formation of protective barriers, activation the reaction of hypersensitivity and synthesis of antimicrobial peptides, which are low molecular weight compounds showing broad spectrum activity against fungi, bacteria and viruses. This group consists of several groups of peptides, including defensins, which are one of the most common classes of antimicrobial peptides and are detectable in all living organisms. Defensins are small (45-54 amino acids), cysteine-rich peptides involved in a different protective responses (B.P. Thomma et al., 2002). Genes which are coding plant defensins are expressed in different organs of plants, where their products are necessary for biotic and abiotic stresses. Thus, these peptides are extremely important in terms of getting crop lines that are resistant to pathogens and abiotic stresses. Defensins are characterized by a strong sequence variability that seems to correlate with a variety of mechanisms of action of these peptides that can induce pathogen's cell death by penetrating into a cell or by being on its surface (T.M. Shafee et al., 2016). Most of the plant defensins are characterized by the antifungal activity. Some defensins have antibacterial activity, which may be combined with activity against fungi. For a small number of plant defensins their participation in the processes of resistance to heavy metals, cold stress, drought, salinity, and in the development process is indicated. Modern approaches of molecular and computational biology allow an effective search for new forms of defensins activity by studying the wild, non-model plant objects. The development of next-generation sequencing methods («Next Generation Sequencing») make possible the intensive study of the transcriptomes of such objects. However, the correct annotation of the sequences of peptides, characterized by small size and high variability, can be done by usage the special programs, such as SPADA (Small Peptide Alignment Discovery Application) (P. Zhou et al., 2013). SPADA makes multiple sequence alignment of all known paralogous genes within a gene family and builds a predictive model for the search of new members of the same family. Prediction of newly identified active defensins and identification of conserved amino acids can also be performed by computational biology methods. An approach based on a multiple sequence alignment and subsequent cluster analysis allows dividing defensins into groups with similar functional activity (N.L. van der Weerden et al., 2013). Thus, the combination of modern methods of molecular and computational biology allows carrying out the study of this group of protective peptides with high efficiency.

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“…Its preferential occurrence in ovules is reflected by the amount of OPDA, JA, and their amino acid conjugates and methyl esters, measured in pistils, all accumulating to high levels markedly exceeding that of leaves . The ovary-specific accumulation of jasmonates might result in expression of JA-induced genes, such as proteinase inhibitors (PIN2; Pena-Cortes et al, 1991), Leu amino peptidases (Fowler et al, 2009), endo-b-1,4-glucanase and g-thionins (Milligan and Gasser, 1995), and defensins (Lay et al, 2003), all of them expressed in female flower organs. This suggests a specific role of JA and/or other oxylipins in ovules of tomato flowers.…”

mentioning

confidence: 99%

Role of cis-12-Oxo-Phytodienoic Acid in Tomato Embryo Development

Goetz

Hellwege²,

Stenzel³

et al. 2012

Plant Physiology

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Oxylipins including jasmonates are signaling compounds in plant growth, development, and responses to biotic and abiotic stresses. In Arabidopsis (Arabidopsis thaliana) most mutants affected in jasmonic acid (JA) biosynthesis and signaling are male sterile, whereas the JA-insensitive tomato (Solanum lycopersicum) mutant jai1 is female sterile. The diminished seed formation in jai1 together with the ovule-specific accumulation of the JA biosynthesis enzyme allene oxide cyclase (AOC), which correlates with elevated levels of JAs, suggest a role of oxylipins in tomato flower/seed development. Here, we show that 35S::SlAOC-RNAi lines with strongly reduced AOC in ovules exhibited reduced seed set similarly to the jai1 plants. Investigation of embryo development of wild-type tomato plants showed preferential occurrence of AOC promoter activity and AOC protein accumulation in the developing seed coat and the embryo, whereas 12-oxo-phytodienoic acid (OPDA) was the dominant oxylipin occurring nearly exclusively in the seed coat tissues. The OPDA-and JA-deficient mutant spr2 was delayed in embryo development and showed an increased programmed cell death in the developing seed coat and endosperm. In contrast, the mutant acx1a, which accumulates preferentially OPDA and residual amount of JA, developed embryos similar to the wild type, suggesting a role of OPDA in embryo development. Activity of the residual amount of JA in the acx1a mutant is highly improbable since the known reproductive phenotype of the JA-insensitive mutant jai1 could be rescued by wound-induced formation of OPDA. These data suggest a role of OPDA or an OPDA-related compound for proper embryo development possibly by regulating carbohydrate supply and detoxification.

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Isolation and Properties of Floral Defensins from Ornamental Tobacco and Petunia

Cited by 200 publications

References 50 publications

Flower-specific jasmonate signaling regulates constitutive floral defenses in wild tobacco

Flower-specific jasmonate signaling regulates constitutive floral defenses in wild tobacco

PLANT DEFENSINS: BIOLOGICAL FUNCTION, MECHANISMS OF ACTION AND METHODS OF ANALYSIS (review)

Role of cis-12-Oxo-Phytodienoic Acid in Tomato Embryo Development

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