Phylogenetic and Expression Analysis of Pear Yellow Stripe-Like Transporters and Functional Verification of <Emphasis Type="Italic">PbrYSL4</Emphasis> in Pear Pollen

Yellow stripe-like (YSL) family transporters, belonging to the oligopeptide transporter family, are significant iron transport proteins. In this study, we provided a genome-wide identification and analysis of the YSL gene family in Pyrus bretschneideri. We found eight YSL gene members in pear, clustered into four main groups in the phylogenetic tree. Segmental duplication has played a key role in the expansion of the pear YSL family. The pollen activity analysis indicated that the low concentration of iron ion was beneficial to both pear pollen germination and pollen tube growth. Among the eight YSL genes, PbrYSL4 had particularly high expression in all pear tissues; it was significantly responsive to change in the external iron ion supply in the pollen cultivation in vitro. Moreover, expression of PbrYSL4 in yeast mutant Δccc1 (Ca ²⁺ -sensitive cross-complementer 1 mutant) made Δccc1 restore growth in high iron medium. These data together suggest that PbrYSL4 was involved in the movement of iron in the pear pollen tube growth.     

N-acetylcysteine prevents the development of gastritis induced by <Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection

Helicobacter pylori (H. pylori) is a human gastric pathogen, causing various gastric diseases ranging from gastritis to gastric adenocarcinoma. It has been reported that combining N-acetylcysteine (NAC) with conventional antibiotic therapy increases the success rate of H. pylori eradication. We evaluated the effect of NAC itself on the growth and colonization of H. pylori, and development of gastritis, using in vitro liquid culture system and in vivo animal models. H. pylori growth was evaluated in broth culture containing NAC. The H. pylori load and histopathological scores of stomachs were measured in Mongolian gerbils infected with H. pylori strain 7.13, and fed with NAC-containing diet. In liquid culture, NAC inhibited H. pylori growth in a concentration-dependent manner. In the animal model, 3-day administration of NAC after 1 week from infection reduced the H. pylori load; 6-week administration of NAC after 1 week from infection prevented the development of gastritis and reduced H. pylori colonization. However, no reduction in the bacterial load or degree of gastritis was observed with a 6-week administration of NAC following 6-week infection period. Our results indicate that NAC may exert a beneficial effect on reduction of bacterial colonization, and prevents the development of severe inflammation, in people with initial asymptomatic or mild H. pylori infection.     

Knockout of <Emphasis Type="Italic">OsACOS12</Emphasis> caused male sterility in rice

Pollen development in flowering plants is critical for male reproductive success. The pollen wall that protects the pollen from various environment stresses and bacterial infections plays an essential role in pollen development. The formation of pollen wall is associated with the biosynthesis and transport of sporopollenin components. ACOS5 in Arabidopsis encodes an acyl-CoA synthetase 5 required for sporopollenin biosynthesis. We identified the rice homolog of ACOS5 as OsACOS12. The CRISPR/Cas9-mediated OsACOS12 knockout mutant has complete male sterility due to a defect in pollen wall formation. β-Glucuronidase reporter gene analysis and RNA in situ hybridization indicated that OsACOS12 was specifically expressed in tapetum and microspores. The subcellular localization of OsACOS12-YFP demonstrated that OsACOS12 protein was primarily localized in the endoplasmic reticulum and nucleus. Our results suggest that OsACOS12 plays a critical and conserved role in pollen wall formation and pollen development and has implications in rice breeding.