OsGLP3‐7 positively regulates rice immune response by activating hydrogen peroxide, jasmonic acid, and phytoalexin metabolic pathways

Abstract

Although germin‐like proteins (GLPs) have been demonstrated to participate in plant biotic stress responses, their specific functions in rice disease resistance are still largely unknown. Here, we report the identification and characterization of OsGLP3‐7 , a member of the GLP family in rice. Expression of OsGLP3‐7 was significantly induced by pathogen infection, jasmonic acid (JA) treatment, and hydrogen peroxide (H 2 O 2 ) treatment. OsGLP3‐7 was highly expressed in leaves and sublocalized in the cytoplasm. Overexpression of OsGLP3‐7 increased plant resistance to leaf blast, panicle blast, and bacterial blight, whereas disease resistance in OsGLP3‐7 RNAi silenced plants was remarkably compromised, suggesting this gene is a positive regulator of disease resistance in rice. Further analysis showed that OsGLP3‐7 has superoxide dismutase (SOD) activity and can influence the accumulation of H 2 O 2 in transgenic plants. Many genes involved in JA and phytoalexin biosynthesis were strongly induced, accompanied with elevated levels of JA and phytoalexins in OsGLP3‐7 ‐overexpressing plants, while expression of these genes was significantly suppressed and the levels of JA and phytoalexins were reduced in OsGLP3‐7 RNAi plants compared with control plants, both before and after pathogen inoculation. Moreover, we showed that OsGLP3‐7 ‐dependent phytoalexin accumulation may, at least partially, be attributed to the elevated JA levels observed after pathogen infection. Taken together, our results indicate that OsGLP3‐7 positively regulates rice disease resistance by activating JA and phytoalexin metabolic pathways, thus providing novel insights into the disease resistance mechanisms conferred by GLPs in rice.

Molecular Characterization of Germin-like Protein Genes in Zea mays (ZmGLPs) Using Various In Silico Approaches

“…79 Recently, OsGLP3-7 provides protection against leaf blast, panicle blast, and bacterial blight mainly expressed in leaves and the cytoplasm. 32 A similar response was also reported for HvGERs (chromosome 8) against Blumeria graminis f. sp. hordei in barley.…”

“…Previously, 14 OsGLPs located on chromosome 8 acted as a QTL by providing resistance against rice blast and sheath blight . Recently, OsGLP3-7 provides protection against leaf blast, panicle blast, and bacterial blight mainly expressed in leaves and the cytoplasm . A similar response was also reported for HvGER s (chromosome 8) against Blumeria graminis f. sp.…”

“… 79 Recently the role of OsGLP3-7 was confirmed against leaf blast, panicle blast, and bacterial blight by activating JA and phytoalexin metabolic pathways. 32 Similarly, TaGLPs located on 4A, 4B, and 4D chr provide potential resistance against Blumeria graminis f. sp. tritici ( bgt ) infection.…”

“…( 122 ) Recently JA and phytoalexin-mediated protection was noted for OsGLP2-7 against leaf blast, panicle blast, and bacterial blight. 32 …”

“…Previously, 43 Oryza sativa germin-like protein genes (OsGLPs) and their promoters were analyzed using computational tools, which gave significant novel insights into their function and regulation 30,31 with recent reports on OsGER4 and OsGLP3-7. 32,33 Similarly, an analysis of VvGLP3 in Vitis vinifera predicted its role against powdery mildew. 34 A sequence of TaGLP-2b was analyzed with different tools to predict its functional and structural properties.…”