spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online August 4, 2003
doi: 10.1242/10.1242/dev.00655

This Article
Right arrow Summary Freely available
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kim, M.
Right arrow Articles by Sinha, N.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kim, M.
Right arrow Articles by Sinha, N.

Reduced leaf complexity in tomato wiry mutants suggests a role for PHAN and KNOX genes in generating compound leaves

Minsung Kim1, Thinh Pham1,*, Ashley Hamidi1, Sheila McCormick2, Robert K. Kuzoff3,{dagger} and Neelima Sinha1,{ddagger}

1 Section of Plant Biology, University of California, Davis, CA, USA
2 Plant Gene Expression Center, USDA/ARS-University of California, Berkeley, CA, USA
3 Section of Molecular and Cellular Biology, University of California, Davis, CA, USA



View larger version (90K):

[in a new window]
  		Fig. 1. Leaf phenotypes of w, w3 and w6. (A) wild-type unipinnate compound tomato leaf. (B) w6 plants produce, from the base to the apex, less compound leaves with irregularly shaped blades, cup-shaped leaves and wire-like leaves. (C) w3 plants with less compound leaves. Often wire-like leaves produce two ectopic leaves (el) distally and a SAM (star) is formed between the junction of these two ectopic leaves. (D) Scanning electron micrograph of the ectopic meristem in C. (E) w leaves. (F) Axillary buds on w6 plants. Scale bars: (A-C,E,F) 1 cm, (D) 250 µm.

 


View larger version (127K):

[in a new window]
  		Fig. 2. Transverse sections of wild type, w, w3 and w6. The adaxial side is marked by asterisks. (A,B) Wild-type leaf; (C) wild-type stem; (D) wild-type petiole. (E) w3, (G) w6 and (H) w wire-like leaves. (F) w3 leaf with ectopic distal leaves. Vascular bundle arrangement is intermediate between that of leaf and stem. (I) w3 and (J) w6 expanded leaves. (K) w expanded leaf showing normal ab-adaxiality. (L-N) Vascular bundles showing the reduced adaxial domain (arrowheads) in w3 (L), and w6 (M) and abnormal vascular bundle in w expanded leaf (N). p, phloem, x, xylem. Scale bars: (A) 100 µm, (B,E-L) 50 µm, (C) 10 µm, (D) 20 µm, (M,N) 25 µm.

 


View larger version (135K):

[in a new window]
  		Fig. 3. Scanning electron micrographs showing epidermal cells of wild-type and wiry mutant leaves. (A,C,E,G) adaxial and (B,D,F,H) abaxial epidermis of (A,B) wild-type leaves, (C,D) w3 leaves, (E,F) w6 leaves and (G,H) w leaves. Scale bars: (A-H) 20 µm.

 


View larger version (63K):

[in a new window]
  		Fig. 4. Floral organ phenotypes in wild-type (A,E,I,J), w6 (B,F,K), w3 (C,G,L,M) and w (D,H,N). (A-D) Whole flowers. (E,I,J) Wild-type petal showing adaxial epidermis with papillar cells (E,J) and abaxial epidermis with flat cells and trichomes (E,I). (F-N) SEM and sections of wiry mutant petals showed partial (F,K,N) and complete (G,L,M) abaxialization of petals. (K) Trichomes (t) on adaxial (ad) petal epidermis in w6. SEMs of (L) abaxial and (M) adaxial petal epidermal cells in w3. (N) Abaxial patches (ab) were seen in adaxial petal epidermis in w flowers. Scale bars: (A-D) 0.5 cm, (E-N) 50 µm, (L,M) 25 µm.

 


View larger version (96K):

[in a new window]
  		Fig. 5. In situ hybridization showing LePHAN, LeYAB B and KNOX expression patterns in the SAM. (A-F) Wild type, (G-K) w6, (L-O) w3 and (P-S) w. mRNA accumulation patterns for LePHAN (A,B,C,G,L,P), LeYAB B (D,H,I,M,Q), LeT6 (E,J,N,R) and TKN1 (F,K,O,S). (A-C) LePHAN expression in the wild-type SAM and young leaf primordium (A), later stage leaf primordium (B) and leaflet primordia (lp; C). (G,L,P) LePHAN expression in the SAM and young leaf primordium of w6 (G) w3 (L) and w (P). Downregulation of LePHAN was seen in later leaf primordia in w6 (G inset), w3 (L inset) and w (P inset). (D) LeYAB B expression in the wild-type leaf primordium. (H,I,M,Q) YAB B was expressed in both adaxial and abaxial domains of leaf primordium in w6 (H,I), but only in adaxial domain in w3 (M), and no YAB B expression was detected in w leaf primordium (Q). (E) LeT6 expression in the wild-type SAM, leaf primordium and leaflet primordium (E inset). (J) LeT6 expression in the SAM and young leaf primordium in w6, and in later leaf primordia (J inset). (N,R) LeT6 expression in the SAM and the later stages of w3 (N, N inset) and w (R,R inset) leaf primordium. (F,K,O,S) TKN1 expression in wild type (F), w6 (K), w3 (O) and w (S). TKN1 expression in later stages of leaf primordium of w3 (O inset). Scale bars: 50 µm.

 


View larger version (75K):

[in a new window]
  		Fig. 6. Genetic interaction between KNOX genes and LePHAN. (A) Overexpression of LeT6 in Cu leaflets. (B,C) LePHAN expression in the Cu leaf primordia and (C) leaflet primordia. (D-F) LePHAN accumulation in the wild-type and Me plants. (D) A transverse section of a wild-type SAM. (E,F) Transverse sections of (E) Me leaf primordium with narrow adaxial domain, and (F) radial Me leaf. (B,D,E) Asterisks in B,D and E indicate the LePHAN expression domains; M, meristem. (G,H) Reduced Cu phenotypes in antiLePHAN background. Arrowhead points to a radially symmetric expanded petiole. (I) Cu plants showing LeT6 overexpression phenotypes. (J) LePHAN downregulation phenotype in the antiLePHAN leaf. (K,L) Ectopic shoots (*) on adaxial domains in Me leaf. (M-P) Me and w6 phenotypes are dosage sensitive. (M) Unipinnate wild-type (+/+) tomato leaf. (N) Excessively compound leaf in Me/+. (O) Wire-like leaves in Me/Me. (P) w6/+ leaf is more lobed than normal leaves and w6/w6 leaves are wire-like or cup-shaped. Scale bars: (A-F) 50 µm, (K, L) 100 µm, (J) 0.5 cm and (G-I, M-P) 1 cm.

 


View larger version (53K):

[in a new window]
  		Fig. 7. A model showing the regulatory relationship between LeT6 and LePHAN and final leaf morphology in tomato. LeT6 is downregulated when LePHAN is strongly overexpressed. Loss of KNOX gene function or extreme downregulation of LeT6 could be lethal for plants because of the lack of SAM formation/maintenance. Weak LePHAN overexpression might lead to the ectopic leaf blade outgrowth in the rachis region and make large simple leaves. LePHAN and LeT6 levels are well balanced in the wild-type leaf, producing 8-9 leaflets with normal ab-adaxiality. Weak LeT6 overexpression and LePHAN downregulation lead to KNOX overexpression phenotypes seen in the 35S::LeT6 plants (Janssen et al., 1998Go), Me/+ and Cu leaves. Because LeT6 overexpression phenotypes require LePHAN activity, strong LeT6 overexpression and LePHAN downregulation cause LePHAN downregulation phenotypes including cup-shaped or wire-like leaves, severe 35S::LeT6, Me/Me, w6/w6 and Cu/Cu;antiLePHAN/+ leaves.

 




© The Company of Biologists Ltd 2003