Untitled

Abstract

Using a genomic clone encoding a rice lipid transfer protein, LTP1, we analysed the activity of the 5' region of the Ltp1 gene in transgenic rice (Oryza sativa L.) during plant development and under pathogen attack. The -1176/+13, -556/+13 and -284/+13 regions of the promoter were fused upstream from the uidA reporter gene and nos 3' polyadenylation signal, resulting in the pdelta1176Gus, pdelta556Gus and pdelta284Gus constructs which were transferred to rice by microprojectile bombardment. Histochemical and fluorometric GUS assays and in situ detection of uidA transcripts in transgenic homozygous lines harbouring the pdelta1176Gus construct demonstrated that the Ltp1 promoter is preferentially active in aerial vegetative and reproductive organs and that both specificity and level of expression are regulated during organ development. In leaf sheath, GUS activity which is initially strictly localized in the epidermis of growing tissue, becomes restricted to the vascular system in mature tissues. In expanded leaf blade, expression of the uidA gene was restricted to the cutting level suggesting inducibility by wounding. Strong activity was detected in lemma and palea, sterile glumes, and immature anther walls and microspores but not in female reproductive organs. No GUS activity was detected during seed embryo maturation whereas the uidA gene was strongly expressed at early stages of somatic embryogenesis in scutellum tissue. The Ltp1 transcripts were found to strongly accumulate in response to inoculation with the fungal agent of the blast disease, Magnaporthe grisea, in two rice cultivars exhibiting compatible or incompatible host-pathogen interactions. Analysis of pdelta1176Gus leaf samples inoculated with the blast fungus demonstrated that the Ltp1 promoter is induced in all cell types of tissues surrounding the lesion and notably in stomata guard cells. In plants harbouring the Ltp1 promoter deletion construct pdelta556Gus, activity was solely detected in the vascular system of mature leaves whereas no uidA gene expression was observed in pdelta284Gus plants. These observations are consistent with the proposed role of LTP1 in strenghtening of structural barriers and organ protection against mechanical disruption and pathogen attack.

Two maize END-1 orthologs, BETL9 and BETL9like, are transcribed in a non-overlapping spatial pattern on the outer surface of the developing endosperm

“…Consequently, it would be very surprising to find a single nsLTPs in vivo function. Indeed, some nsLTPs have shown antimicrobial activity in vitro and the expression of their encoding genes is induced after pathogen infection, suggesting that they could be involved in defense against these invaders (Molina and García-Olmedo, 1993, 1997; Guiderdoni et al, 2002; Gomès et al, 2003). For those nsLTPs their defensive role would be acting like toxic weapons, but for the Arabidopsis DIR1 (defective in induced resistance1) nsLTP it would be carrying, or chaperoning, a still unknown systemic signal that triggers defensive responses in parts of the plant still free of the pathogen (Maldonado et al, 2002; Champigny et al, 2013).…”

Insight into the Molecular Evolution of Non-Specific Lipid Transfer Proteins via Comparative Analysis Between Rice and Sorghum

“…9,17 Furthermore, the nsLTP genes from some plants are expressed in the leaf epidermal cell layer, where the waxy cuticle is generally found. 9,18 However, more complex expression profiles from individual experiments are frequently observed, such as expression in the xylem, phloem, or stigma, which can lead to disparate and unpredictable gene functions of nsLTPs. 11–13 …”

Cutin monomer induces expression of the rice OsLTP5 lipid transfer protein gene

“…Accumulating evidence suggests that LTP expression is responsive to environmental stresses including salt, drought, cold treatment (Vignols et al, 1997;Arondel et al, 2000;Yubero-Serrano et al, 2003;Jung et al, 2006;Kim et al, 2006), and treatment with signaling molecules such as abscisic acid (ABA), salicylic acid (SA), ethylene, and methyl jasmonate (Vignols et al, 1997;Garcia-Garrido et al, 1998;Jung et al, 2006;Kim et al, 2006). Expression of LTP is protective against fungal and viral infection (Garcia-Olmedo et al, 1995;Blilou et al, 2000;Guiderdoni et al, 2002;Park et al, 2002;Jung et al, 2006;Kim et al, 2006;Chassot et al, 2007). It has been reported that LTP is involved in long-distance signaling during acquisition of systemic acquired resistance (SAR) in Arabidopsis thaliana (Maldonado et al, 2002).…”

“…The differential expression of three LTP genes, representing classes I, II, and III, in response to salt, ABA, and SA was analyzed using germinated seeds and young plants (Vignols et al, 1997;Kim et al, 2006). Inoculation with the fungal agent of the rice blast disease, Magnaporthe grisea, caused strong accumulation of transcripts of the class I LTP gene during the early hours of infection (Guiderdoni et al, 2002;Kim et al, 2006).…”