Adaptation of the of Sesbania virgata to the storage compounds of the seeds

Marco Aurélio S. Tiné

Instituto de Botânica, São Paulo, Brazil Sesbania virgata. (Cav.) Pers. Seed Morphology Mobilisation of the storage galactomannan in seeds of Sesbania

virgata. Fotos: cortesia Fotos: de Patricia P.Tonini. Structure of the galactomannan

Mannose/ Carbon metabolism and transport

Sink

source

Transport sink Mannose is described as toxic to some plants: Induces cell death and DNA fragmentation in maize. Mannose is descibed as toxic to some plants: It also inhibits photosynthesis in maize.

Mannose metabolism in corn and its impact on leaf metabolites, photosynthetic gas exchange and chlorophyll fluorescence. Harris, G.C., Gibbs, P.M., Ludwig, G., Un, A., Sprengnether, M. (1986).Plant Physiol. 82:1081-1089. Mannose is descibed as toxic to some plants: And inhibits seed germination in arabidopsis. Procedure Imbibition of the seeds in solutions (suc, glc, man, water, intact seed.)

Remove endosperm after 2 days

Grow the seedlings in carbohydrate solution for 8 days

Transition heterotrophy autotrophy Grow on a greenhouse for 21 days. The lenght of the embryo is also reduced when is present in the surroundings.

12 s/w/o endo endo manoseMannose 10 glucoseGlucose a,a c/W endo endo 8 b 6 a

lenght (cm) lenght b

4 c c d 2 glc inhibits extension

0 3 5 7 Days Analyzing the weight: Glucose interferes in water uptake, but mannose dos not. Fresh 0,05 Dry weight 0,6 Embrionary axis Mannose 0,04 w/o endo 0,4 Glucose 0,03 w/ endo 0,02

Fresh (g) Fresh Mannose 0,2 mass Dry (g) w/o endo 0,01 Glucose w/ endo 0,0 0 2 4 days 6 8 2 4 6 8 days

Mannose 0,6 Cotyledons Mannose w/o endo w/o endo 0,20 Glucose Glucose 0,5 w/ endo w/ endo 0,4 0,10 Dry mass (g) Dry a Fresh mass(g) Fresh 0,3 b

0,2 0,00 2 4 6 8 2 4 6 8 days days analysis: Glucose induces the accumulation of starch.

0 ,1 2 M a n o s e

d 0 ,1 0 s / e n d o g lu c o s e c

0 ,0 8 c / e n d o c c

0 ,0 6

b % d e a m id o 0 ,0 4 b

b b 0 ,0 2 a a a a 0 ,0 0 2 d ia s 4 d ia s 6 d ia s 8 d ia s

After 21 days, there is a correlation between the content in the source (cotyledons) and the leaf area.

8 a a,b leaf 2 leaf 1

6 b cot

) 2

4 c c (cm

2

rea a 0 with w/o man glc suc cotyledon 1st leaf 2nd leaf sucrose 0.496 0.717 0.910 100

1)

- 80

60

40

20

Treatment with glucose (ug.mgconc. suc 0 reduces leaf area. com sem suc man glc tratamento By adding increasing concentrations of we manage to saturate the “usual” pathways:

When we add We get (in the cotyledons) 25 mM galactose Galactonic acid 25 mM Xylonic acid 50 mM glucose or sucrose (cot) Gluconic acid

But we never got mannonic acid. Even going up to 100 mM of mannose PCA of the metabolic profiles of the cotyledons in 20mM solutions of .

6 2 4 5 6 4 8 21 3

2

1

0 -6 -4 -2 0 2 4 6 -1

-2 Change in the ammount of the four metabolites with higher loadings in the cotyledons.

600 with 500 citrate sucrose with w/o w/o suc 400 suc man 400 man glc 300

glc

ion countion ion count ion

200 200

100

0 0 0 5 10 15 20 25 0 5 10 15 20 25 days days

1000 glucose 400 myo-inositol

with 800 w/o 300 with suc w/o 600

man suc ion count ion ion count ion 200 man 400 glc glc 100 200

0 0 0 5 10 15 20 25 0 5 10 15 20 25 days days) As a general pattern:

oGlucose inhibits embryo extension; oGlucose induces accumulation of starch; oGlucose reduces leaf expansion. which inhibits carbon assimilation. Mannose does not have these effects. So besides the function of protection against predators, the use of galactomannan also allows a system of signalling were: Mannose: Glucose: Storage compounds Photosynthesis mobilisation. stablished. Thank you.

Marco Aurélio S. Tiné [email protected]