Sugarcane Cell Wall-Associated Defense Responses to Infection by Sporisorium scitamineum

Abstract

The plant cell wall is known to be the first barrier against plant pathogens. Detailed information about sugarcane cell wall-associated defense responses to infection by the causal agent of smut, Sporisorium scitamineum, is scarce. Herein, (immuno)histochemical analysis of two smut resistant and two susceptible sugarcane cultivars was conducted to understand host cell wall structural and compositional modifications in response to fungal infection. Results showed that the fungus grew on the surface and infected the outermost bud scale of both susceptible and resistant cultivars. The present findings also supported the existence of early (24 h after inoculation) and later (72–96 h after inoculation) inducible histopathological responses related to the cell wall modification in resistant cultivars. Lignin and phenolic compounds accumulated during early stages of infection. Later infection response was characterized by the formation of a protective barrier layer with lignin, cellulose and arabinoxylan in the cell walls. Overall, the results suggest possible induction of cell wall-modified responses in smut resistant cultivars to prevent initial entry of the fungus into the meristematic tissues.

Time-series expression profiling of sugarcane leaves infected with Puccinia kuehnii reveals an ineffective defense system leading to susceptibility

“…Transcripts annotated with the lignin biosynthetic process term (GO:0009809) showed a substantial decrease in expression in the first time point after inoculation, with some reestablishment at 48 hai (Fig 2-A). Lignin deposition in the epidermis is an important event to prevent sugarcane infection by S. scitamineum at 24 hai [102]. We observed that almost all genes of cinnamyl-alcohol dehydrogenase (CAD), a precursor of lignin biosynthesis, returned to their basal expression level after marked downregulation at 12 hai.…”

Persistent Calyxes in Postbloom Fruit Drop: A Microscopy and Microanalysis Perspective

“…The protocol established by Marques et al [37] was used to verify the presence of C. acutatum hyphae in petal and calyx tissues. The glass slides were treated with a WGA-Alexa Fluor 488 dilution according to the manufacturer (Life ® ) for 30 min and then washed in water once for 3 min.…”

An actin‐depolymerizing factor from the halophyte smooth cordgrass, Spartina alterniflora (SaADF2), is superior to its rice homolog (OsADF2) in conferring drought and salt tolerance when constitutively overexpressed in rice

“…O 2À and H 2 O 2 were visualized in situ following Jabs et al (1996) and Thordal-Christensen et al (1997), respectively. Transmission electron microscopy (Marques et al, 2018) and scanning electron microscopy (Baisakh et al, 2012) were conducted to examine chloroplast ultrastructure and stomata, respectively (Method S1). All quantitative data were analysed statistically for variance (ANOVA), and treatment means were compared by Tukey's HSD in XLSTAT add-in of Microsoft Excel.…”