ABSTRACT

The appressoria that are generated by the rice blast fungus Magnaporthe oryzae in response to surface cues are important for successful colonization. Previous work showed that regulators of G-protein signaling (RGS) and RGS-like proteins play critical roles in appressorium formation. However, the mechanisms by which these proteins orchestrate surface recognition for appressorium induction remain unclear. Here, we performed comparative transcriptomic studies of Morgs mutant and wild-type strains and found that M. oryzae Aa91 (MoAa91), a homolog of the auxiliary activity family 9 protein (Aa9), was required for surface recognition of M. oryzae. We found that MoAA91 was regulated by the MoMsn2 transcription factor and that its disruption resulted in defects in both appressorium formation on the artificial inductive surface and full virulence of the pathogen. We further showed that MoAa91 was secreted into the apoplast space and was capable of competing with the immune receptor chitin elicitor-binding protein precursor (CEBiP) for chitin binding, thereby suppressing chitin-induced plant immune responses. In summary, we have found that MoAa91 is a novel signaling molecule regulated by RGS and RGS-like proteins and that MoAa91 not only governs appressorium development and virulence but also functions as an effector to suppress host immunity.

IMPORTANCE The rice blast fungus Magnaporthe oryzae generates infection structure appressoria in response to surface cues largely due to functions of signaling molecules, including G-proteins, regulators of G-protein signaling (RGS), mitogen-activated protein (MAP) kinase pathways, cAMP signaling, and TOR signaling pathways. M. oryzae encodes eight RGS and RGS-like proteins (MoRgs1 to MoRgs8), and MoRgs1, MoRgs3, MoRgs4, and MoRgs7 were found to be particularly important in appressorium development. To explore the mechanisms by which these proteins regulate appressorium development, we have performed a comparative in planta transcriptomic study and identified an auxiliary activity family 9 protein (Aa9) homolog that we named MoAa91. We showed that MoAa91 was secreted from appressoria and that the recombinant MoAa91 could compete with a chitin elicitor-binding protein precursor (CEBiP) for chitin binding, thereby suppressing chitin-induced plant immunity. By identifying MoAa91 as a novel signaling molecule functioning in appressorium development and an effector in suppressing host immunity, our studies revealed a novel mechanism by which RGS and RGS-like proteins regulate pathogen-host interactions.

The outer segments (OS) of rod and cone photoreceptor cells are specialized sensory cilia that contain hundreds of opsin-loaded stacked membrane disks that enable phototransduction. The biogenesis of these disks is initiated at the OS base, but the driving force has been debated. Here, we studied the function of the...

Kei Jokura, Junko M. Nishino, Michio Ogasawara, and Atsuo Nishino

Ciliary movement is a fundamental process to support animal life, and the movement pattern may be altered in response to external stimuli under the control of nervous systems. Juvenile and adult ascidians have ciliary arrays around their pharyngeal gill slits (stigmata), and continuous beating is interrupted for seconds by mechanical stimuli on other parts of the body. Although it has been suggested that neural transmission to evoke ciliary arrest is cholinergic, its molecular basis has not yet been elucidated in detail. We herein attempted to clarify the molecular mechanisms underlying this neurociliary transmission in the model ascidian Ciona. Acetylcholinesterase histochemical staining showed strong signals on the laterodistal ciliated cells of stigmata, hereafter referred to as trapezial cells. The direct administration of acetylcholine (ACh) and other agonists of nicotinic ACh receptors (nAChRs) onto ciliated cells reliably evoked ciliary arrest that persisted for seconds in a dose-dependent manner. Only one isoform among all nAChR subunits encoded in the Ciona genome, called nAChR-A7/8-1, a relative of vertebrate α7 nAChRs, was expressed by trapezial cells. Exogenously expressed nAChR-A7/8-1 on Xenopus oocytes responded to ACh and other agonists with consistent pharmacological traits to those observed in vivo. Further efforts to examine signaling downstream of this receptor revealed that an inhibitor of phospholipase C (PLC) hampered ACh-induced ciliary arrest. We herein propose that homomeric α7-related nAChR-A7/8-1 mediates neurociliary transmission in Ciona stigmata to elicit persistent ciliary arrest by recruiting intracellular Ca²⁺ signaling.

C. M. Lind, J. Agugliaro, and T. M. Farrell

Mounting an immune response may be energetically costly and require the diversion of resources away from other physiological processes. Yet, both the metabolic cost of immune responses and the factors that impact investment priorities remain poorly described in many vertebrate groups. For example, although viviparity has evolved many times in vertebrates, the relationship between immune function and pregnancy has been disproportionately studied in placental mammals. To examine the energetic costs of immune activation and the modulation of immune function during pregnancy in a non-mammalian vertebrate, we elicited an immune response in pregnant and non-pregnant pygmy rattlesnakes, Sistrurus miliarius, using lipopolysaccharide (LPS). Resting metabolic rate (RMR) was measured using flow-through respirometry. Immune function was examined using bactericidal assays and leukocyte counts. The RMR of pygmy rattlesnakes increased significantly in response to LPS injection. There was no statistically significant difference in the metabolic response of non-reproductive and pregnant snakes to LPS. Mean metabolic increments for pregnant females, non-reproductive females, and males were 13%, 18%, and 26%, respectively. The ratio of heterophils to lymphocytes was elevated in response to LPS across reproductive categories; however, LPS did not impact plasma bactericidal ability in non-reproductive snakes. Although pregnant females had significantly higher plasma bactericidal ability compared to non-reproductive snakes prior to manipulation, their bactericidal ability declined in response to LPS. LPS administration also significantly reduced several litter characteristics, particularly when administrated relatively early in pregnancy. Our results indicate that immune performance is energetically costly, altered during pregnancy, and that immune activation during pregnancy may result in tradeoffs that affect offspring in a viviparous reptile.

And I’m sick of it.

Ingram also called ITV's new drama about his cheating scandal 'terrifyingly accurate' and 'excruciatingly enjoyable'

Pietro Nivola offers two cheers, instead of three, for the American political system in light of the latest global economic concerns. He argues that since 2008, the federal government has not committed many basic economic blunders, but fiscal policy could improve on the state and local levels.

The big Danish design competition really has similar goals to TreeHugger: to promote good green design that makes the world better

Doctors in India are governed by the regulations of Medical Council of India (MCI). MCI is an apex body that has reg

This evening’s Square E3 press was…something. After more than an hour of Final Fantasy remasters, the publisher closed things out with far and away its most eagerly awaited game. Licensing some white hot IP, the RPG masters at Square are offering up their own take on Earth’s mightiest heroes. Bay Area-based Crystal Dynamics addressed what […]

Ioan Gruffudd is set to return to ITV's Liar as Andrew Earlham next month. Father-of-two who lives in LA, says he's now 'old and weathered enough' to represent anti-heroes.

Welsh-born Ioan Gruffudd, 46, told The Guardian that he couldn't wait to get his teeth into the character after reading the script, but the 'horrible things he's done' took their toll on him during filming.

Joanne Froggatt promoted series two of Liar alongside co-star Katherine Kelly in London on Thursday, in her first public appearance since announcing her split from husband James Cannon.

Jesse Lingard has had his fair share of detractors to deal with over the years, but even he would have been taken aback by the abuse he received trying to board the team bus at Derby County.

Fabio Quagliarella endured more than five years of harrowing paranoia, secrecy and torment. His family were abused in the street, his beloved city of Naples cast him out as a traitor.

Kim Jong-un turned up the heat on South Korea on Friday as he visited a newly-built spa in the North, while calling for a meeting with Seoul about tearing down a jointly-built resort, calling it 'shabby'.

Princess Charlotte, five, posed for her obligatory first day of school family photo in her uniform this morning beside her brother Prince George, six - on the familiar steps of Kensington Palace.

The Project's Peter Helliar, 42, avoids discussing PMS symptoms with his co-hosts, in hilarious segment on Tuesday's program.

The Project's Peter Helliar was not nominated for a Gold Logie this year. And on Monday, the comedian was mocked for being snubbed of an award nomination on Have You Been Paying Attention ?

The 34-year-old former semi-finalist of American Idol took to his Instagram Story early Tuesday morning for several critical posts aimed at the 39-year-old wife of Kanye West.

Shane Sutton sensationally stormed out of the Richard Freeman medical tribunal on Tuesday after branding the former Team Sky and British Cycling medic a 'spineless liar'.

'Last year, I promised to support the Republican nominee. And I intend to keep my word,' Cruz wrote on Facebook, adding that 'by any measure Hillary Clinton is wholly unacceptable.'

Retiring senator Dan Coats of Indiana unloaded on Ted Cruz, saying he 'only thinks of himself' and is a 'narcissistic, pathological liar.

Khabib Nurmagomedov's manager Ali Abdelaziz has called out Conor McGregor and his team as they prepare for the Irishman's upcoming fight against Donald Cerrone.

He is regarded as one of Australia's best comedians.

They triumphantly won the Silver Logie on Sunday night for Most Popular Panel or Current Affairs Program. 

Text messages revealed in new court documents claim the Duke and Duchess of Sussex tried to protect Thomas Markle in the days leading up to their wedding.

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He recently spoke candidly about how stress had lead to a secret health battle.

Charlie Sheen, 51, told the Kyle and Jackie O Show on Wednesday, that his former co-star Jenny McCarthy, 44, is a liar, after the busty blonde claimed that he should have disclosed his HIV status.

The poll, released Thursday by Quinnipiac University, asked more than 1500 registered voters to say the 'first word' that comes to mind when they hear the name of the presidential candidates.

England found out on Saturday that their Group D opponents at Euro 2020 will be Croatia, Czech Republic, and either Scotland, Serbia, Israel, or Norway.

England found out on Saturday that their Group D opponents at Euro 2020 will be Croatia, Czech Republic, and either Scotland, Serbia, Israel, or Norway.

Merle Gorman, 83, who previously served in the United States Marine Corp, made international news after he accused Biden of selling access to the Presidency through son Hunter.

Donald Trump lashed out at Democrats in a fiery tweet Saturday morning. He insisted that he never referred to the coronavirus a 'hoax' and called Democrats liars.

Romelu Lukaku scored after just 22 seconds and added another goal to help Inter Milan to a 4-1 victory over Cagliari at San Siro on Tuesday and a place in the Italian Cup quarter-final.

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The new iPhone SE has the body of an iPhone 8 with the 'brains' of an iPhone 11 thanks to Apple's latest A13 Bionic chip, which enables it to capture Portrait Mode photos.

On hearing that his dark and, at times, almost unbearably moving comedy had been recommissioned, Ricky Gervais said, 'I have never had a reaction like this before. It's been insane.'

Inter Milan want to secure Christian Eriksen from Tottenham in time for next weekend's match with Cagliari. They need to increase their offer of £15m to convince Tottenham to sell.

Jesse Lingard has had his fair share of detractors to deal with over the years, but even he would have been taken aback by the abuse he received trying to board the team bus at Derby County.

Both the Supreme Court and the Prime Minister recognised that rehabilitation for Sardar Sarovar dam on the Narmada river was incomplete, but neither was willing to fulfil their legal responsibility to actually stop construction. Instead, the the Shunglu Committee is now "independently" investigating rehabilitation and it appears compromised, worries Mike Levien.

As the nuclear world appears poised to pry open a vast market for power plants and arms in India, Darryl D'Monte reports voices from a corner of the world that was witness to an earlier, Soviet-era nuclear rush.

Disregard for local sentiment is now the norm in most large projects. At Tadadi, which has faced a long line of threats of displacement, the latest struggle is against a proposed 4000 MW coal-fired plant. With Coastal Zone regulators not very attentive to the violations of law, the villagers can rely only on themselves. Sudhirendar Sharma reports.