Blufensin1Negatively Impacts Basal Defense in Response to Barley Powdery Mildew    

Abstract

Plants have evolved complex regulatory mechanisms to control the defense response against microbial attack. Both temporal and spatial gene expression are tightly regulated in response to pathogen ingress, modulating both positive and negative control of defense. BLUFENSIN1 (BLN1), a small peptide belonging to a novel family of proteins in barley (Hordeum vulgare), is highly induced by attack from the obligate biotrophic fungus Blumeria graminis f. sp. hordei (Bgh), casual agent of powdery mildew disease. Computational interrogation of the Bln1 gene family determined that members reside solely in the BEP clade of the Poaceae family, specifically, barley, rice (Oryza sativa), and wheat (Triticum aestivum). Barley stripe mosaic virus-induced gene silencing of Bln1 enhanced plant resistance in compatible interactions, regardless of the presence or absence of functional Mla coiled-coil, nucleotide-binding site, Leu-rich repeat alleles, indicating that BLN1 can function in an R-gene-independent manner. Likewise, transient overexpression of Bln1 significantly increased accessibility toward virulent Bgh. Moreover, silencing in plants harboring the Mlo susceptibility factor decreased accessibility to Bgh, suggesting that BLN1 functions in parallel with or upstream of MLO to modulate penetration resistance. Collectively, these data suggest that the grass-specific Bln1 negatively impacts basal defense against Bgh.

Foxtail Mosaic Virus-Induced Gene Silencing in Monocot Plants

“…By contrast, to date only four RNA viruses and one DNA virus have been modified as vectors for VIGS in monocot species, of which, Barley stripe mosaic virus (BSMV)-based VIGS has been applied for functional genomics in barley (Hordeum vulgare L.) and wheat (Triticum aestivum; Holzberg et al, 2002;Tai et al, 2005;Meng et al, 2009;Pacak et al, 2010;Yuan et al, 2011); Brome mosaic virus (BMV) in rice (Oryza sativa L.), barley, and maize (Zea mays L.; Ding et al, 2006); Bamboo mosaic virus and its satellite RNA in N. benthamiana and Brachypodium distachyon (Liou et al, 2014); and Rice tungro bacilliform virus in rice (Purkayastha et al, 2010). Very recently, Cucumber mosaic virus-based VIGS in maize is reported (Wang et al, 2016) BMV and BMV-based vectors are frequently used for VIGS in some monocot plants.…”

Transient Virus Expression Systems for Recombinant Protein Expression in Dicot- and Monocotyledonous Plants

“…TMV and PVX VIGS vectors were the first to employed in this manner in the dicot N. benthamiana, with BSMV used shortly after in the monocot barley [84,100]. Since these first reports, vector systems for functional genomics have continued to be refined and optimized in an expanding number of hosts [18,87], including systems amenable for high throughput screens in monocots based on BSMV [101,102].…”

Differential accumulation of host mRNAs on polyribosomes during obligate pathogen-plant interactions

“…Total and polysomal RNAs were extracted from barley seedling first leaves (PO:0007094) of both CI 16151 (Mla6) and its fast-neutron deletion mutant, mla6-m9472, 20,24 at 32 HAI with Bgh isolate 5874 (AVR a6 ) as well as from noninoculated (control) plants of each genotype (Fig. 1A).…”

“…8 Subsequent functional analyses have shown that barley genes possessing this expression pattern play key roles in Bgh susceptibility and resistance. 17,20 Turnip mosaic virus (TuMV) is a potyvirus that causes diseases on many vegetable crops, and it infects the model plant Arabidopsis. DNA microarray studies have shown that TuMV can cause considerable quantitative and qualitative changes in host mRNA expression.…”