SKIP Silencing Decreased Disease Resistance Against Botrytis cinerea and Pseudomonas syringae pv. tomato DC3000 in Tomato.

Huijuan Zhang,Ming Jiang,Fengming Song,Longfei Yin

doi:10.3389/fpls.2020.593267

Abstract

SKIP, a component of the spliceosome, is involved in numerous signaling pathways. However, there is no direct genetic evidence supporting the function of SKIP in defense responses. In this paper, two SKIPs, namely, SlSKIP1a and SlSKIP1b, were analyzed in tomato. qRT-PCR analysis showed that the SlSKIP1b expression was triggered via Pseudomonas syringae pv. tomato (Pst) DC3000 and Botrytis cinerea (B. cinerea), together with the defense-associated signals. In addition, the functions of SlSKIP1a and SlSKIP1b in disease resistance were analyzed in tomato through the virus-induced gene silencing (VIGS) technique. VIGS-mediated SlSKIP1b silencing led to increased accumulation of reactive oxygen species (ROS), along with the decreased expression of defense-related genes (DRGs) after pathogen infection, suggesting that it reduced B. cinerea and Pst DC3000 resistance. There was no significant difference in B. cinerea and Pst DC3000 resistance in TRV-SlSKIP1a-infiltrated plants compared with the TRV-GUS-silencing counterparts. As suggested by the above findings, SlSKIP1b plays a vital role in disease resistance against pathogens possibly by regulating the accumulation of ROS as well as the expression of DRGs.

Highlights

The splicing process is completed by spliceosome, which can be classified as two types, including major spliceosome and minor spliceosome (Moore and Proudfoot, 2009; Turunen et al, 2013)
Using the characterized Arabidopsis AtSKIP genes as queries, a tomato genomic database was searched by Blastp analysis, and two loci were identified in tomato genome, which were named as SlSKIP1a (XM_004251580.4) and SlSKIP1b (XM_004250540.4)
After 72 h of Pst DC3000 infection, the SlSKIP1b level was notably upregulated by about 6.3 times relative to that in control plants with mimic inoculation, whereas the SlSKIP1a level showed no difference after Pst DC3000 infection (Figure 1A)

Summary

Introduction

The splicing process is completed by spliceosome, which can be classified as two types, including major spliceosome and minor spliceosome (Moore and Proudfoot, 2009; Turunen et al, 2013). SKIP, one of the splicing factors and important components of spliceosome, has possessed several conserved domains (including the SNW/SKI-interacting protein, SKIP) and the specific motifs (Folk et al, 2004; Bres et al, 2009; Chen et al, 2011; Wang et al, 2012). In Arabidopsis, the SNW domain can integrate into spliceosome in the meantime of interacting with the Paf complex (Li et al, 2016). SKIP is a component of the 35S-U5snRNP complex, which participates in the common RNA splicing directly (Albers et al, 2003). Growing evidence shows that SKIP is involved in transcription regulation and RNA splicing through interacting with different proteins and takes parts in regulating several

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