A wheat xylanase inhibitor gene, Xip-I, but not Taxi-I, is significantly induced by biotic and abiotic signals that trigger plant defense.
XIP-I and TAXI-I are wheat (Triticum aestivum L) grain proteins that inhibit microbial xylanases used in food processing. Although their biochemical properties and structural features were established recently, very little is known about their expression and their family members in wheat plants. To clarify the role of these xylanase inhibitor proteins in plant defense, we examined the expression of the XIP-type genes in response to a variety of biotic and abiotic signals. Although Xip-I was not expressed in flowering spikelets inoculated with Fusarium graminearum, transcription of Xip-I was greatly enhanced in Erysiphe graminis-infected leaves. Thus, unlike Taxi-I, Xip-I is pathogen-inducible, and unlike Taxi-III and Taxi-IV, its expression depends on the type of the pathogen and/or infected tissue. Xip-I was expressed when the leaves were wounded, and its expression was significantly elevated by treatment with methyl jasmonate (MeJA). The different expression profiles of XIP- and TAXI-type genes suggest distinct roles in plant defense.
Igawa
Tomoko
T
Laboratory for Remediation Research, Plant Science Center, RIKEN, Saitama.
Tokai
Takeshi
T
Kudo
Toshiaki
T
Yamaguchi
Isamu
I
Kimura
Makoto
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000737:chemistry; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves; D010940:Plant Proteins / Q000096:biosynthesis* / Q000737:chemistry; D018520:Plant Shoots; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction; D014908:Triticum / Q000378:metabolism* / Q000382:microbiology; D015854:Up-Regulation
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010940:Plant Proteins; C422246:TAXI I protein, Triticum aestivum; C485063:XIP-I protein, Triticum aestivum