PUNCTATE VASCULAR EXPRESSION1Is a Novel Maize Gene Required for Leaf Pattern Formation That Functions Downstream of the Trans-Acting Small Interfering RNA Pathway      

Abstract

The maize (Zea mays) gene RAGGED SEEDLING2-R (RGD2-R) encodes an ARGONAUTE7-like protein required for the biogenesis of trans-acting small interfering RNA, which regulates the accumulation of AUXIN RESPONSE FACTOR3A transcripts in shoots. Although dorsiventral polarity is established in the narrow and cylindrical leaves of rgd2-R mutant plants, swapping of adaxial/abaxial epidermal identity occurs and suggests a model wherein RGD2 is required to coordinate dorsiventral and mediolateral patterning in maize leaves. Laser microdissection-microarray analyses of the rgd2-R mutant shoot apical meristem identified a novel gene, PUNCTATE VASCULAR EXPRESSION1 (PVE1), that is down-regulated in rgd2-R mutant apices. Transcripts of PVE1 provide an early molecular marker for vascular morphogenesis. Reverse genetic analyses suggest that PVE1 functions during vascular development and in mediolateral and dorsiventral patterning of maize leaves. Molecular genetic analyses of PVE1 and of rgd2-R;pve1-M2 double mutants suggest a model wherein PVE1 functions downstream of RGD2 in a pathway that intersects and interacts with the trans-acting small interfering RNA pathway.

Trans-acting small interfering RNA4: key to nutraceutical synthesis in grape development?

“…The activity of tasiRNAs as repressors of endogenous target mRNAs in Arabidopsis and maize ( Zea mays ) involves AGO1 as well as AGO7 (for TAS3a-c ) [19, 20] and is triggered by a two miRNA hit model [4, 21, 22] or through initial targeting by longer 22 nt miRNAs [23, 24] or a bulged miRNA-miRNA* duplex [25]. In the TAS -specific pathway of RNAi, RNA DEPENDENT RNA POLYMERASE6 (RDR6) copies the miRNA-cleaved TAS product into dsRNA with the help of plant-specific SUPPRESSOR OF GENE SILENCING3 (SGS3) [26].…”

Getting closer: vein density in C4 leaves

“…Mutations in the maize gene PUNCTATE VASCULAR EXPRESSION1 ( PVE1 ), encoding a biochemically unknown protein, led to plants with small ectopic leaves and leaf outgrowths, and abnormal vascular development (Zhang et al ., ). PVE1 acts downstream of RAGGED SEEDLING2‐R ( ZmRGD2‐R ), which encodes an ARGONAUTE7‐like protein required to coordinate dorsiventral and mediolateral patterning.…”

Ontogeny of the sheathing leaf base in maize (Zea mays)

“…HOMEODOMAIN-LEUCINE ZIPPERIII (HD-ZIPIII) genes have well-described functions during adaxial patterning and vascular development (McConnell & Barton, 1998;McConnell et al, 2001;Emery et al, 2003;Juarez et al, 2004;Itoh et al, 2008). Transcript localization of the maize genes ROLLED1 (RLD1) (Juarez et al, 2004) and ZmPHABULOSA1 (ZmPHAB) (Juarez et al, 2004;Zhang et al, 2012) were re-examined by in situ hybridization. Both RLD1 and ZmPHAB1 are expressed in adaxial domains of leaf primordia and in developing vascular bundles, as described previously (Fig.…”